Does your child know how to add and subtract 3-digit numbers and 100? Invite them to practice this concept here. Subtraction is the inverse of addition and vice versa. Students apply this relationship to solve a set of problems in add and subtract 3-digit numbers and 100 worksheet. In each problem, the numbers are laid out in the horizontal format. Students should try to use different strategies involving composing and decomposing numbers to solve these problems. This will help them develop flexibility and fluency.