# Place Value

## Rounding

Rounding is a process by which we make long, detailed numbers easier to understand (or estimate with).

The most general definition of rounding is to simplify a number, by cutting off the details, to a particular place value. When dealing with numbers in the millions, do you really need to know the details in the hundreds and thousands? If not, you can round to the nearest million.

## Place Value

We use a base-10 number system which means that each digit in a number is worth ten times the digit to its right.

When dealing with whole numbers, the number farthest to the right is the ones digit. That place value tells how many wholes (less than 10) are in the number.

Take the number:

**1, 234, 567, 890**

*In this number, there are:*

0 ones