Dividing by 10 and 100

Dividing by 10 undoes multiplying by 10, so the point moves one place to the left. $\frac{38.2}{10}$ is 3.82: every digit drops to a place worth ten times less.

For 100 the point moves two places left, and for 1000 three: again one place per zero. When the digits run out on the left, fill with zeros: $\frac{7.5}{100}$ is 0.075. The point moves past the 7 and one more place, so a 0 holds the tenths.

A quick check: dividing by 100 should make a number much smaller, and 0.075 is much smaller than 7.5, so the point moved the right way. This is how cents become dollars: 250 cents divided by 100 is 2.50 dollars.