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

Well, he used one box to decorate his yard, that's for sure. Then he used 40 from the other box to decorate his porch and the rest inside his house. That rest might be anything between 1 and infinity. So there were at least 41 balloons in each box. I think the question is incomplete, please doublecheck it so I'll be able to give you more specific result.