Decimals are numbers with parts less than 1, like 3.5.
Rounding a decimal is finding a number that's simpler than the decimal you start with.
For example, imagine a boy needs to ride his bike 3.14 miles to get to the bus stop. 🚴
Instead of saying the boy biked 3.14 miles, we can round and say the boy biked about 3 miles.
That's called rounding to the nearest whole number.
Rounding to the nearest whole number is the same as rounding to the Ones place.
We looked at the digit to the right of the target, and since it was less than 5 we rounded down.
Let's round some decimals together to different places.
Round 48.32 to the nearest whole number.
1️⃣ First, find the target digit.
Very good! It's 8.
2️⃣ Now, look at the digit to the right of the target digit.
This is the digit 3, in the Tenths place.
If this digit is less than 5, round down.
If this digit is 5 or more, round up.
What should we do? 🤔
3 is less than 5, so we round down.
Rounding down means dropping all the digits to the right of the target digit.
So let's round down our number.
48.32 rounded to the nearest whole number is 48.
Great job.
Round 716.943 to the nearest whole number.
What's the target digit?
It's the digit 6 in the Ones place.
What digit is to the right of it?
9.
9 is more than 5.
So we round up.
Rounding up means adding one to the target, and turning all other digits to the right of the target to 0.
Let's round up our number.
716.943 rounded to the nearest whole number is 717. ✅
Round 17.24 to the nearest tenths.
1️⃣ What's our target digit?
Yes, it's 2 in the Tenths place.
Tip: Be careful that you don't confuse the Tenths place with the Tens place.
7 is in the Tens place. 2 is in the Tenths place.
2️⃣ Now look at the digit to its right.
It's 4.
4 is less than 5. That means we need to round down.
17.24 rounded to the nearest tenth is 17.2.
Great work. Let's do one more example.
Round 857.146 to the nearest Hundredth.
The target digit is 4 in the Hundredths place.
Tip: Don't confuse Hundredths with the Hundreds place.
Look at the digit to the right of 4.
It's the digit 6.
We need to round up because 6 is more than 5.
Excellent work.
Now, complete the practice to master rounding decimals on your own.