Practice 10 more, 10 less, 1 more, 1 less, with this worksheet and teaching tool. An awesome and simple little teaching tool to go with your 100's chart. This is a great way for students to learn to visualize how to add and subtract by 10's. Included is a worksheet where students can roll a dice to choose a number in the middle, or use the number of the day in the middle to use all week long.