The Little Box Magic

This week we have been learning about subtraction and addition, but mostly subtraction. So we did a little activity with a big box and a little box. We put a number in the little box and then put the little box in the big box and then magic happened.I liked making my boxes. I found it difficult writing the right words in the text. The learning behind this task was to help us learn more about subtraction.
Can you solve what magic happened?