Round the number to the thousandths place.

64,672.318498

A.

65,000

B.

64,672.318

C.

64,672.319

D.

64,672.32

Here's how decimals work:

0.000

Tenths place

Hundredths place

Thousandths place

This goes on and on and on.

The other rule of decimals is "Five or above, give it a shove. Four or below, let it go.

This means that if the number in the place after the place you want to round to (in this case the ten-thousandths place) is ≥5, you round up. If it's ≤4, you round down.

In this case, the answer is B. 64,672.318 because eight is in the thousandths place and the number that comes after it is four.