Rounding
Round whole numbers to a given place value.
Objective
Round whole numbers to a given place value.
What it means
Rounding replaces a number with a nearby number that is easier to work with, based on a chosen place value.
Key terms
- Rounding digit
- The digit in the place you are rounding to.
- Test digit
- The digit just to the right of the rounding digit, used to decide rounding direction.
Rules to remember
- If the test digit is 5 or more, round the rounding digit up by 1.
- If the test digit is less than 5, keep the rounding digit the same.
- All digits to the right of the rounding digit become 0.
Step by step
- 1Find the placeUnderline the digit in the place you're rounding to.
- 2Check the next digitLook at the digit right after it.
- 3Round up or keep5 or more rounds up; less than 5 stays the same. Replace remaining digits with 0.
Common mistakes
- Rounding based on the wrong digit.
- Forgetting to zero out digits after the rounding place.
Tips
- Circle the test digit before deciding to remind yourself which one matters.