16.5÷10 = 1.65
explain how you decided where to place the decimal

Think about the question. In division, if you divide by 1, the number stays the same. If you divide by a larger number (like 10), the answer will get smaller. Therefore, you know to move the decimal to the left.

Here, there is one zero after the 1, so you move the decimal back one space. If it was divided by 100, the answer would be 0.165