Question

A girl wrote 7 tens Instead of 7 tenths by how much was her answer wrong?

Answer 1

well, let's scope out the scale of the problem, take it step by step...

First, we need to know the range.:
7 tens is essentially 7 times ten, or 70.
7 tenths is 7/10, or .7
So, subtract .7 from 70 to get the difference of 69.3, which is your answer.

Answer 2

Her answer was wrong by a factor of 10² .

That means it was 100 times too large.