Greg bought 2 boxes of balloons. he used half of them to decorate his yard. he used 40 to decorate his porch. he used the rest inside his house. how many balloons did he use inside?

Greg had balloons to decorate inside the house.

Step-by-step explanation:

Lets say Greg has N number of balloons per box.

So, in total he had 2N balloons.

He used half of 2N to decorate the yard.

So, we have N balloons left.

Out of N, he used 40 to decorate his porch.

Then again the left number of balloons will be =

Therefore, Greg had balloons to decorate inside the house.