If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

# 3rd grade (U.S.)

3rd grade is full of some of the most important ideas in mathematics. You'll extend the addition and subtraction that you did in second grade to more than two digits. You will also get your first exposure to the ideas of multiplication, division, and fractions, which will be used the rest of your mathematical lives (we'll even use some letters as placeholders for unknown numbers along the way). 3rd grade is also when we first think about area (how much "space" something takes on a surface) and perimeter (the distance around a shape). All of that will be rounded out by making sure that you can apply these ideas in the real world and see patterns in the mathematical world. (Content was selected for this grade level based on a typical curriculum in the United States.)
Community Questions
Place value and rounding
Going a bit deeper with our understanding of place value from 2nd grade. We'll apply this knowledge to learn to round things to the nearest 10 and 100.
All content in “Place value and rounding”

### Rounding

Rounding is useful when you are trying to roughly estimate numbers. Common Core Standard: 3.NBT.A.1