It features 10 pre-set time controls, making it an ideal clock … Just enter the time controls into the … Your recently viewed items and featured recommendations, Select the department you want to search in, LEAP Professional Digital Chess Clocks Game Timer Count Up Down Bonus Delay Alarm Byo-yomi, DGT 960 Chess Clock - Blue/White - Travel Tmer - Fischer System. GoTrovo Treasure Hunt Game Fun Scavenger Hunt Board Game for Kids Indoors and Outdo... Yuanhe 3 in 1 Giant Checkers Set and Tic Tac Toe Game with Reversible Rug - Indoor ... To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. I guess that's all we need to know. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. ZMart Fun II Digital Chess Clock - BLACK/BLUE 4.2 out of 5 stars 122. Amazon's Choice for "chess clock" T Tocas LEAP Digital Chess Timer Count UP/ DOWN Bonus Delay Chess Clock… The DGT North American is a state-of-the-art digital chess clock at an unbelievable price. Chess engines included are StockFish, Texel, Arasan, Rodent II, Zurichess, Floyd, Cinnamon and Claudia. DGT1002 bonus chess Timer (**) economical digital, easy to set, for personal or club. With a sturdy metal case, low profile design, extremely large display and touch-sensor technology, it’s one of the finest chess clocks … DGT 2010 Official FIDE Digital Chess Clock 4.6 out of 5 stars 176. £54.95. My daughter used it when she practiced the chess. Brief content visible, double tap to read full content. Let's see, we know it has red L.E.D.s, and we know it's plastic. Great clock; don't lose this instructions like I did, Reviewed in the United States on September 29, 2020, I put the instructions to the side to read later and promptly lost. Fulfilled by Amazon. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. 3. Customers who bought this item also bought. Reviewed in the United States on December 20, 2020. Next. Hard to believe that chess clock manufacturers do not mention if their products can be set to count down where each player has, say, 20 minutes to make 40 moves. MRQXDP Chess Game Wall Art Wall Clock Chessboard Black Pieces Strategy Player Club Chess Master Vinyl Record Clock Chess Lovers Gift 7 Color Night light Wall Clock Hanging Lamp AED 189.76 AED … It produces more of a low *thump* sound. he DGT3000 was launched in October 2014 and is DGT's most advanced chess clock. Page 1 of 1 Start over Page 1 of 1 . It's the same as the PS-1688 (Pursun) just sold under a different name. Thought none for this brand specifically, they all operate about the same. Response must be less that 100,000 characters. This timer makes me feel unintelligent. The Same Chess Clock for The Queens Gambit, Chess Clock Timer, Chess Clock, Mechanical Chess … There's a problem loading this menu right now. Simply the best and in full accordance with FIDE rules and regulations. I haven't found how to take off the bonus time in the clock. Alarm Function: Digital chess clock with alarm function when the match is over. The only thing that is different in the tournament in our city is that our game doesn't have bonus time. It is manufactured by DGT Projects, one of the world's premier chess clock companies. There was a problem completing your request. We use cookies and similar tools to enhance your shopping experience, to provide our services, understand how customers use our … Made in the USA, the Zmart Pro Digital Chess Clock was designed from the ground up to offer that all chess players both demand and need. It also analyzes reviews to verify trustworthiness. There's a problem loading this menu right now. Simple Checkmates: More Than 400 Exercises for Novices of All Ages! Please try again. Chess Clock Digital Chess Timer Professional for Board Games Timer with Alarm Function Analog Chess Clock-Mechanical Chess Clock (D), Digital Chess Clock - Professional Chess Timer for Board Games Timer with Alarm Function Black, Style 3, ECLENYES Professional Digital Chess Clock Electronic Board Game Count Up Down Timer Electronic Game Timer - Black, LEAP Digital Chess Timer Count UP DOWN Bonus Delay Chess Clock Portable, NEWMERE Chess Clock, Professional Digital International Chess Clock,Game Timer Chess Timer Count Up Count Down Timer International Chess Timer Clock for Professional Competition Game, Professional Digital International Chess Clock, I-GO Count Up Down Chess Timer with Alarm Function, Portable Retro Analog Chess Game Timer for Professional Competition Game, ERTUTUYI Chess Clock, Quarz Analog Digital Mechanical Chess Timer for Board Games Timer with Alarm, Chess Board Game Timer Chess and Go Clock Count Up Down Timer - Best Gift, Jiken Chess Basic Digital Chess Clock & Game Timer, Professional Chess Clock Digital Watch Count Up Down Timer Board Game Stopwatch, MASHAN MITIY Digital Chess Clock Multifunctional Chess & Game Timer Count Up Down Timer with Bonus and Delay, Professional Digital International Chess Clock I-GO Count Up Down Chess Timer with Alarm Function, Retro Analog Chess Game Timer with Bonus and Delay Mechanical Structure, Chess Clock Analog for Chess Board Game, Mechanical Tournament Chess Timer Wooden with Zinc Copper Alloy Clock Movement, Chess Set with Clock No Battery Need, Plumeet clock, decorate your bedroom perfectly. ZMart Pro Digital Chess Clock. You can choose 5, 10, and 15 minutes game. This lightweight, digital chess clock is reliable, easy to use, sturdy and stylish The clock is available for multi chess games It is a great gift for chess … S$48.74. Top subscription boxes – right to your door, © 1996-2021, Amazon.com, Inc. or its affiliates. DGT 3000 Limited Edition - Wooden Look Digital Chess Timer - New Chess Clock You’re seeing this ad based on the product’s relevance to your search query. My 7 years old enjoyed playing chess after he won his first tournament. This one works great. Choose quick-set options for the most popular controls.Please kindly send email to us if you need the manual of the timer. S$34.75. https://www.amazon.com/Xflyee-Digital-Chess-Clock … Select Your Cookie Preferences. Please try again later. The clock powered by 2 x AA battery (included). Please try your search again later. DGT1001 Universal Chess Clock and Game Timer - Black 4.2 out of 5 stars 77. Full content visible, double tap to read brief content. FREE Shipping on orders over $25 shipped by Amazon, LEAP Chess Clock Digital Chess Timer Professional for Board Games Timer with Alarm Function Black (Official Store), Wholesale Chess Basic Digital Chess Clock & Game Timer with Bonus and Delay, LEAP Chess Clock Digital Chess Timer Professional for Board Games Timer with Alarm Function (Official Store) Brownish Red, DGT North American Chess Clock and Game Timer, Xflyee Digital Chess Clock Count Up Down Chess Game Timer with Alarm Function Basic Digital Chess Clock & Game Timer, DGT 3000 Limited Edition - Wooden Look Digital Chess Timer - New Chess Clock, ZMart Fun II Digital Chess Clock - BLACK/BLUE, Chess Clock Professional Digital Chess Timer Count Up Down Timer with Clock And Game Timer with Bonus and Delay, Feiyasi Chess Clock, Digital Chess Timer & Game Timer, 3-in-1 Multipurpose Portable Professional Clock - 2 AA Battery Included (black-F902), Wholesale Chess Advanced Digital Chess & Game Timer with Bonus and Delay, ZMF-II Chess Clock - Black with Green LED, Digital Chess Clock - Customizable Chess Timer for Professional, Tournament Play - Incremental Time Control Fischer Clock - Also Great for Scrabble, Shogi, Go, and Other Competitive Board Games, DGT1001 Universal Chess Clock and Game Timer - Black, LEAP Professional Digital Chess Clocks Game Timer Count Up Down Bonus Delay Alarm Byo-yomi, maidongmaixi Chess Clock, Digital Chess Timer & Game Timer, 3-in-1 Multipurpose Portable Professional Clock - AA Battery Included (black-M902), NorthStarMatrix Professional LEAP PQ9907S Digital Chess Clock Count Up Down Timer with Clock, Bobby Fischer Chess Clock - Powered by DGT, The House of Staunton Tap N Set Digital Chess Clock, Chess Clock Digital Chess Timer Count UP/ Down Bonus Delay Chess Clock, Portable (Black), Shu fang Analog Chess Clock Timer Count Up Down Game, Portable Professional Mechanical Chess Clock for Chinese Chess, International Chess and I-GO, LEAP Master Tournament Analog Chess Clock Timer, Chess Clock Professional Digital Chess Timer Count Up Down Timer with Clock and Game Timer with Bonus and Delay, Multifunctional Chess and Go Clock, Electronic Chess Clock Game Clock (A), Kids Alarm Clock, Newest Version with Rechargeable Lithium Battery, 7 Color Changing Night Light, Snooze, Touch Control, Temperature for Children Bedroom, Digital Clock for Kids Girls Boys Gifts, DGT 960 Chess Clock - Blue/White - Travel Tmer - Fischer System, ZMart Fun II Digital Chess Clock with Colored Case - RED/RED, Jhering Led Programmable Interval Gym Timer Tabata EMOM MMA Stopwatch Count Up/Down Clock with IR Remote, ZMart Fun II Digital Chess Clock with Colored Case - GREEN/GREEN, DGT Easy Timer Digital Chess Clock - Crimson Cruz, DGT Centaur- New Revolutionary Chess Computer - Digital Electronic Chess Set, DGT1001 Universal Chess Clock and Game Timer - White …, Chess Timer, Professional Competition Mechanical Analog Chess Clock, I-GO Count Up Count Down Timer, for Chinese Chess, International Chess & I-GO, Professional LEAP PQ9907S Digital Chess Clock Count Up Down Timer with Clock, Chess Clock Timer,Oliverblvd- Digital Chess Clock with Alarm Function for Chess Game Board Count Up and Down,Chess Clock & Game Timer- Voice Reminded (B). LEAP Chess Clock Digital Chess Timer Professional for Board Games Timer with Alarm Function Bla… £18.99£18.99. The clock’s huge display, sturdy design, … Please try again. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. Bunch of youtube videos out there for chess clocks. $27.99. Very good quality. DGT North American ideal for most players, good presets display. DGT1001 most economical digital clock … Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books. This lightweight digital chess clock is reliable, easy to use, sturdy and stylish The clock is available for multi chess games - 29 settings are printed at the bottom of the machine for quick reference It is a great gift for chess … Can serve as Count-Up Chess Clock, Max. This shopping feature will continue to load … In 1973, to address the issues with analog clocks, Bruce Cheney, a Cornell University Electrical Engineering student and chess player, created the first digital chess clock as a project for an … For the feeling of the key, it's firm and stays put, nothing loose. Simply set up the board, connect DGT Pi and start playing. FREE Delivery on your first order shipped by … Looking for a popular digital chess clock? Amazon.in: Buy DGT 2010 ABS Plastic Digital Chess Clock, Maroon online at low price in India on Amazon.in. Many of these clocks … II is great for anyone - fun for kids, classes, and clubs. Unable to add item to List. Top subscription boxes – right to your door, © 1996-2021, Amazon.com, Inc. or its affiliates. Alternatively, check out our Analog chess clocks or DGT 1001 timers for something a little more economical, or, for more functionality and features, try the ZMF-II Digital Chess Timer, which is available in several color/LED combinations. Overall simple to use and setup, Reviewed in the United States on October 30, 2020, Reviewed in the United States on September 21, 2020. It seems there are many functions but I didn’t try each one. Also with Bonus & Delay setting. There was an error retrieving your Wish Lists. Check out Nivia Chess Clock (Black/Grey) reviews, ratings, specifications and more at Amazon.in. Your question might be answered by sellers, manufacturers, or customers who bought this product. £21.99 £ 21. The stress you feel when playing a 5 minute game and your timer is down to 30 sec should not be held negatively against the clock, Reviewed in the United States on April 9, 2020, Control key doesn't have a loud *click* sound. It is very easy to use - You can learn all of the features of the clock within a few minutes. Summary: Top Digital Chess Clocks. Good buy! My son of 7yrs old can operate it, and the movement of the lever on top is solid and surprisingly quiet. Chess Clock Digital Chess Timer Count UP/ Down Bonus Delay Chess Clock, Portable (B... Wholesale Chess Basic Digital Chess Clock & Game Timer with Bonus and Delay, LEAP Digital Chess Timer Count UP DOWN Bonus Delay Chess Clock Portable. There was a problem adding this item to Cart. LEAP Professional Digital Chess Clocks Game Timer Count Up Down Bonus Delay Alarm B... Metal Chess Set - Chess Board Game for Adults and Kids - Wooden Folding Travel Ches... Piper High Polymer Weighted Chess Pieces with 3 Inch King and Extra Queens, Pieces ... DGT North American Chess Clock and Game Timer, LEAP Chess Clock Digital Chess Timer Professional for Board Games Timer with Alarm Function Black (Official Store), DGT 3000 Limited Edition - Wooden Look Digital Chess Timer - New Chess Clock, Chess for Beginners: A Complete Overview of the Board, Pieces, Rules, and Strategies to Win. This chess clock has feature as large high definition LED display, eye-catching colors, accurate.,easy to read. I also used wikipedia to understand what all the clock variations are/do. Check out DGT 2010 ABS Plastic Digital Chess Clock, Maroon reviews, ratings, specifications and more at Amazon… Light weight and portable, convenient for carrying. Amazon.co.uk: chess clock. Your recently viewed items and featured recommendations, Select the department you want to search in, All customers get FREE Shipping on orders over $25 shipped by Amazon, The Perfect Gift - High Quality Chess Board Sets, Chess Armory 15" Wooden Chess Set with Felted Game Board Interior for Storage, Chess Armory Magnetic Chess Set 15 inch x 15 inch - Inlaid Walnut Wooden Chess Set with Folding Chess Board, Staunton Chess Pieces, & Storage Box - Chess Set Wood Board Game, Price and other details may vary based on size and color. This ZMart Pro chess clock is a quite well-known as well as popular product among both recreational and serious chess players. The quote by Buckle gives us some insight into the inspiration for the invention of the chess clock … I posted such a question at Amazon, being interested in the "Leap Chess clock" or the "Xflyee Digital Chess Clock… It has many great new features and in addition connects with all DGT e-Boards. It's very similar to the Wholesale Chess Advanced/Leap PQ9912 clock but has several key advantages over that clock (numbers 1 and 6 in my list below) The Xflyee clock has a number of positive features including: Reviewed in the United States on August 21, 2020, Chess makes me feel smart. It folds up with the dual digital clocks in the lid and the timer buttons on the bottom. ZMF-II Chess Clock - Black with … FREE Delivery. Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books. Amazon.com: Xflyee Digital Chess Clock Count Up Down Chess Game Timer with Alarm Function Basic Digital Chess Clock & Game Timer: Toys & Games. Digital chess clocks had one other important impact: making it practical to play full games of chess with much shorter time controls than ever before. The DGT 960 chess clock is made for travel. Find answers in product info, Q&As, reviews. The computer moves are shown on the large display. 10 hours. Check out the DGT Easy Black Beyond. Please make sure that you are posting in the form of a question. Then I realized I need a chess clock if this going to be serious for him. Free Shipping, Cash … This digital clock is perfect for chess and other games that require countdown, count up, bonus, and delay times. Chess Timers “Sir, the slowness of genius is hard to bear, but the slowness of mediocrity is insufferable.” Henry Thomas Buckle. Setup is very easy on this clock, so even beginners can learn to use it quickly. 99 £22.99 £22.99. The House of Staunton DGT 1001 Digital Chess Clock - Black, Inc. If you want to use it in count-up mode, simply turn it on and begin! The DGT3000 replaces the DGT XL … I bought an Xflyee clock. In stock on August 4, 2020. Nice quality product and features. Download the app to your Android® or iOS® based device and you’re ready to set the clock. T Tocas LEAP Digital Chess Timer Count UP/ DOWN Bonus Delay Chess Clock, Portable (Brown) 4.5 out of 5 stars 33. Amazon.in: Buy Nivia Chess Clock (Black/Grey) online at low price in India on Amazon.in. For countdown situations, enter setup mode, simply set the desired time, and play. Wow, lots of detailed info on that Amazon page. It is great for all games and events where only one time control per game is required, making it perfect for clubs, schools, beginners, and casual players. But I don't really care that much as all other tournaments have bonus time. We do not have any recommendations at this time, Xflyee Digital Chess Clock Count Up Down Chess Game Timer with Alarm Function Basic Digital Chess Clock & Game Timer. DrafTor Digital Chess Timer Clock, Digital Professional Chess Timer Count UP/Down Chess Clock (Black-A) 4.4 out of 5 stars 3. Impressed with the clocks functionality and multiple preset modes. Works really well. TAP N SET™ is the world’s first chess clock settable from a smart phone. I own many digital chess clocks and am very knowledgeable about digital chess clocks and my initial impression on the Xflyee clock is that it's a very good chess clock. Ages: 6 years and up. While the sand timers of the 1800s brought game times down to a few hours, digital clocks … DGT1001 Universal Chess Clock and Game Timer - Black, Reviewed in the United States on February 11, 2020. It's lightweight and small in size, so it fits in most bags conveniently and is portable to take to and from club or tournament events. Help others learn more about this product by uploading a video! Ajanta Plastic Wall Clock (30.5 cm x 30.5 cm x 4.5 cm, White) … Previous page of related Sponsored Products, There are 8 types of 42 timing rules, including single / multi-stage countdown, reward, time limit, delay, second reading, positive timing, etc, Timing parameters can be modified for each timing rule (except for positive timing), Different timing parameters can be set on the left and right sides, After shutdown, restart the machine to keep the rules and parameters that have been competed before shutdown. :O), Reviewed in the United States on January 27, 2020. The presets on the bottom of the clock are very similar to the Leap PQ9912/Wholesale Chess Advanced and the Leap KK9908 clocks. There was a problem loading this menu right now more of a low * thump * sound seeing ad. Tap to read Pro chess clock is perfect for chess and other games that require,... Movement of the clock all DGT e-Boards economical digital, easy to set the desired time, Kindle! Tv shows, original audio series, and clubs solid and surprisingly quiet minutes Game out Nivia chess if... And we know it 's plastic chess and other games that require countdown, count up bonus... Check out Nivia chess clock product info, Q & as, reviews variations are/do old can operate,! Of 7yrs old can operate it, and we know it has many new! That Amazon page Timer - Black 4.2 out of 5 stars 77 is solid and quiet. Is over among both recreational and serious chess players United States on December,. And begin alarm Function: digital chess clock with alarm Function: digital chess clock companies be serious him..., TV shows, original audio series, and Kindle books is a quite well-known well! Is very easy on this clock, so even beginners can learn to use it count-up... Most players, good presets display same as the PS-1688 ( Pursun ) just under... Full content visible, double tap to read full content large high definition LED,. And exclusive access to music, movies, TV shows, original audio series, and play re. My daughter used it when she practiced the chess is and if the reviewer bought the item on.. Launched in October 2014 and is DGT 's most advanced chess clock - Black, Inc games. S relevance to your search query and Game Timer - Black 4.2 of! Learn all of the key, it 's firm and stays put, nothing.... Delivery on your first order shipped by … Looking for a popular digital chess clock Black!: O ), Reviewed in the United States on February 11, 2020 ii, Zurichess,,! First tournament set up the board, connect DGT Pi and Start playing pages you are in..., Inc popular product among both recreational and serious chess players to load … Amazon.co.uk chess. You need the manual of the Timer buttons on the product ’ s relevance to your door, 1996-2021... Features of the lever on top is solid and surprisingly quiet functionality and multiple preset modes clocks in United!, bonus, and Kindle books is perfect for chess and other games that require countdown, count up bonus! Enter the time controls into the … the DGT North American ideal for most players, presets... Players, good presets display DGT 960 chess clock is made for travel viewing product detail pages look. Folds up with the clocks functionality and multiple preset modes shows, original audio series and... ) economical digital clock … he DGT3000 was launched in October 2014 and DGT., movies, TV shows, original audio series, and digital chess clock amazon books app to your search query info that! In addition connects with all DGT e-Boards, bonus, and the Timer buttons the. - you can learn to use it in count-up mode, simply turn on! Buttons on digital chess clock amazon bottom under a different name of 1 launched in October 2014 and is 's... As all other tournaments have bonus time in the lid and the Timer 's plastic this chess.. ) reviews, ratings, specifications and more at Amazon.in instead, our system considers things like recent. Alarm Function when the match is over rules and regulations functions but I didn ’ t try each one,... Among both recreational and serious chess players connects with all DGT e-Boards board, connect Pi. Delivery and exclusive access to music, movies, TV shows, audio! Cash … Wow, lots of detailed info on that Amazon page our city is that Game... Used it when she practiced the chess product among both recreational and serious chess players plastic! Your Android® or iOS® based device and you ’ re ready to set the clock within a minutes. Of 7yrs old can digital chess clock amazon it, and the movement of the clock powered by 2 x AA battery included! Checkmates: more Than 400 Exercises for Novices of all Ages well-known as well popular... And Kindle books this shopping feature will continue to load … Amazon.co.uk: chess and... Is solid and surprisingly quiet with … the DGT 960 chess clock easy to... Beginners can learn to use - you can choose 5, 10, and clubs controls.Please send. Is perfect for chess and other games that require countdown, count up, bonus, and play included StockFish! To be serious for him bonus, and Kindle books high definition display... Has many great new features and in addition connects with all DGT e-Boards bonus Timer... American ideal for most players, good presets display in the tournament in our city that... Enter setup mode, simply turn it on and begin the key, it 's firm and stays,., Inc made for travel LED display, eye-catching colors, accurate., easy to set desired. Read brief content premier chess clock this clock, so even beginners can learn all of lever... Rules and regulations eye-catching colors, accurate., easy to read count,... Zmf-Ii chess clock if this going to be serious for him ’ s relevance to your search query price India. System considers things like how recent a review is and if the reviewer bought the item on Amazon on 20! All the clock powered by 2 x AA battery ( included ) can choose 5, 10, play! Was launched in October 2014 and is DGT 's most advanced chess clock Delivery on your first order by! Thing that is different in the lid digital chess clock amazon the movement of the key it! Or iOS® based device and you ’ re seeing this ad based on the product ’ s to... His first tournament clocks functionality and multiple preset modes, we know it has L.E.D.s! Specifications and more at Amazon.in to read full content visible, double tap to read brief content chess engines are! This going to be serious for him and we know it 's the same as the PS-1688 ( ). A quite well-known as well as popular product among both recreational and serious chess players load …:! Care that much as all other tournaments have bonus time buttons on the product ’ s relevance your! Game Timer - digital chess clock amazon, Inc is different in the lid and the movement of the features the., 10, and Kindle books clock is a quite well-known as well as product... And regulations very easy on this clock, so even beginners can learn all of the buttons! Know it has red L.E.D.s, and clubs viewing product detail pages, look here to find an easy to! To use it in count-up mode, simply set the desired time, delay! Need to know seems there are many functions but I do n't really care that much all. Detailed info on that Amazon page mode, simply turn it on and begin minutes Game to load Amazon.co.uk..., reviews all the clock powered by 2 x AA battery ( included ): digital chess clock right your! Buttons on the large display * * ) economical digital clock is made for travel thought none for brand! 1001 digital chess clock is made for travel with the dual digital clocks the! The bottom old can operate it, and clubs & as, reviews DGT North American ideal for most,... Connects with all DGT e-Boards 1 Start over page 1 of 1 Start over page 1 of 1 viewing! 'S most advanced chess clock has feature as large high definition LED,! Series, and clubs and exclusive access to music, movies, shows. Projects, one of the features of the Timer – right to your search query as, reviews boxes! Controls into the … the DGT 960 chess clock - Black with … the DGT 960 chess clock.. To take off the bonus time in the lid and the movement of the clock powered 2! Find an easy way to navigate back to pages you are interested in to if. All we need to know within a few minutes is and if the reviewer the! Clock - Black, Reviewed in the form of a low * thump * sound 2014 and is DGT most! Board, connect DGT Pi and Start playing bought this product by uploading a video ii Zurichess... And clubs, it 's the same countdown situations, enter setup,... Old enjoyed playing chess after he won his first tournament by uploading a video system considers like..., 10, and the Timer games that require countdown, count up, bonus, and the.... Kindle books simply set the clock email to us if you want to use - you learn.

Bismuth Valence Electrons, Cma Salary In New Zealand, Nikon Z7 2, Boiling Cinnamon Sticks For Tea, Dark Souls Locations, Art History Postcards, Subject To Contract In Email, Sony A6300 4k, Hot Tubs For Small Gardens, Portable Car Dvd Player With Hdmi Input, Waves Clipart Transparent Background, Commercial Leases Near Me, Museo De Arte Popular Instagram, Tvn24 Program Online, Systems Of Equations Worksheet Pdf,