How can you give someone $83 using exactly 7 bills, without using any one dollar bills?

Question

A little boy walked up to his uncle and said, ""Uncle, do you know how to make 100 dollars out of ten bills, but not use a single 10 dollar bill?"" ""What do you mean?"" he replied. The little boy replied, "" Make 100 dollars out of any ten bills that aren't a 10."" And so the uncle tried and gave up. But when the boy tried he got it right.

What ten bills, all but the 10 dollar bill, did he use?

Answer 1

50 + 20 + 5 + four times 2 = 83