This is an addition and subtraction worksheet with a twist: in each problem, one of the numbers is missing! To solve, kids must reverse the operations, changing addition to subtraction and subtraction to addition, in order to find the number that goes in the blank. This worksheet offers a gentle introduction to basic algebra; the missing numbers in these problems are the same as variables in algebra.

Want more reverse arithmetic? Print out the rest of the worksheets in the Find the Missing Numbers series.