Can your child find the missing number? This colorful worksheet offers a very gentle introduction to basic algebra. In each problem, your child will reverse the operations, adding for a subtraction problem or subtracting for an addition problem, in order to find the missing number. When he's done, your child will have a better understanding of the relationship between adding and subtracting.
Check out the rest of the worksheets in the Find the Missing Numbers series for more problems like this.