Nico cut out 15 red circles and 10 yellow circles. then he gave away some red circles. how many red circles does nico have left?

Answer=15-x

Given the data, the following expression can be made, where x is equal to the number of red circles he gave away.

15-x

If Nico gave away some red circles and you would like to know how many red circles does he have left, you can calculate this using the following step:

Nico has 15 red circles.

n ... the number of red circles that he gave away

15 - n ... the number of circles that Nico still has

The correct result would be 15 - n.