Decimal place value
Round decimals with one decimal place to the nearest whole number
What a learner can do afterwards
- Round 3.7 to 4 and 3.2 to 3
- Place 6.5 on a number line between 6 and 7 and decide it rounds to 7
- Round a set of one-decimal-place numbers and explain the rounding rule
The lesson
You already know that .7 means seven tenths and .2 means two tenths. Rounding a decimal means picking the closest whole number, so you can drop the tenths and keep one simple number.
Look at 3.7. The digit after the point is 7, and 7 is 5 or more, so 3.7 rounds up to 4.
Now look at 3.2. The digit after the point is 2, and 2 is less than 5, so 3.2 rounds down and stays 3.
Check only the digit right after the point. 0 to 4 means round down. 5 to 9 means round up, even at exactly halfway.
Look at the digit after the point: 5 or more rounds up, 4 or less rounds down.
Watch it
Where it sits
Learn first
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.