Math Worksheets for Kindergarten, 1st, 2nd, 3rd, 4th grade+ - Rocket Math For the first four worksheets you count all the objects in two groups to find the sum. When modeling slash the objects with a pencil as you count. Teach the children to do the same. The answer keys show the objects slashed. Starting in Set E you get the larger of the two numbers "going" and then slash and "count on" from there.