Use this mental math worksheet to deepen understanding of subtraction within 20.

Kids have to write missing numbers in subtraction sentence. In the fisrt task they have to write the missing subtrahend. In the second task they have to write minuend.The last task has mixed problems.

The hidden picture gives kids motivation to write the correct answer.

There is also a reward after each group of tasks.

At the end teacher can see how many attempts kids needed to write missing numbers.