Rounding (Decimal)
See how to round a decimal
(to the nearest tenth, hundredth, thousandth).
4 examples and their solutions.
Rounding
Formula
n...
: 0 ~ 4
→ n
: 5 ~ 9
→ (n + 1)
When rounding a number:: 0 ~ 4
→ n
: 5 ~ 9
→ (n + 1)
If the right side number is in 0 ~ 4,
then don't change n.
If the right side number is in 5 ~ 9,
then n → n + 1.
Example
Round 2.71828... to the nearest hundredth.
Solution 2.71828...
→ 2.72
→ 2.72
Hundredth number: 1
Right side number: 8
8 is in 5 ~ 9.
Then 1 → 1 + 1 = 2.
So write 2.72.
Right side number: 8
8 is in 5 ~ 9.
Then 1 → 1 + 1 = 2.
So write 2.72.
Close
Example
Round 3.141592... to the nearest hundredth.
Solution 3.141592...
→ 3.14
→ 3.14
Hundredth number: 4
Right side number: 1
1 is in 0 ~ 4.
Then don't change 4.
So write 3.14.
Right side number: 1
1 is in 0 ~ 4.
Then don't change 4.
So write 3.14.
Close
Example
Round 3.141592... to the nearest tenth.
Solution 3.141592...
→ 3.1
→ 3.1
Tenth number: 1
Right side number: 4
4 is in 0 ~ 4.
Then don't change 1.
So write 3.1.
Right side number: 4
4 is in 0 ~ 4.
Then don't change 1.
So write 3.1.
Close
Example
Round 3.141592... to the nearest thousandth.
Solution 3.141592...
→ 3.142
→ 3.142
Thousandth number: 1
Right side number: 5
5 is in 5 ~ 9.
Then 1 → 1 + 1 = 2.
So write 3.142.
Right side number: 5
5 is in 5 ~ 9.
Then 1 → 1 + 1 = 2.
So write 3.142.
Close