Rounding to nearest integer

When rounding to the nearest integer, we do exactly the same steps as when rounding to decimal places, but the nth decimal place is the units column (the digit to the left of the decimal point).

Make sure to round up if the next digit is 5 or more, and then we remove all digits after the decimal point.

Examples

Round 4.3 to the nearest integer

The digit we are rounding to is the 4.
The next digit is 3, which is less than 5, so we round down and keep the 4 the same.
Answer: 4.

Round 5.7 to the nearest integer

The digit we are rounding to is the 5.
The next digit is 7, which is more than 5, so we round up and increase the 5 by 1 to get 6.
Answer: 6.

Round 2.5 to the nearest integer

The digit we are rounding to is the 2.
The next digit is 5, which is equal to 5, so we round up and increase the 2 by 1 to get 3.
Answer: 3.

Round 9.99 to the nearest integer

The digit we are rounding to is the 9.
The next digit is 9, which is more than 5, so we round up and increase the 9 by 1 to get 10.
Since 9 becomes 10, we set the units place to 0 and increase the tens place by 1 (which is also 9) to get 10 (so now we have 10.0...).
Answer: 10.

Round 0.49 to the nearest integer

The digit we are rounding to is the 0.
The next digit is 4, which is less than 5, so we round down and keep the 0 the same.
Answer: 0.

Don’t be tempted to round 0.49 to 0.5, which would then round to 1. Always look directly at the digit after the decimal point - don’t try to round in stages!

Round 999.50 to the nearest integer

The digit we are rounding to is the last 9 (the units place).
The next digit is 5, which is equal to 5, so we round up and increase the last 9 by 1 to get 10.
Since 9 becomes 10, we set the units place to 0 and increase the tens place by 1 (which is also 9) to get 10.
We repeat this process for the hundreds place, resulting in 1000.0....
Answer: 1000.

flashcards

Question	Answer
What is the key difference between rounding to the nearest integer and rounding to decimal places?	When rounding to the nearest integer, the nth decimal place is the units column (the digit to the left of the decimal point), rather than a digit to the right.
When rounding to the nearest integer, what is the rule for whether you round up or down?	Round up if the next digit (the first decimal digit) is 5 or more; round down (keep the digit the same) if it is less than 5.
Round 4.3 to the nearest integer.	The digit we are rounding to is the 4. The next digit is 3, which is less than 5, so we round down and keep the 4 the same. Answer: 4.
Round 5.7 to the nearest integer.	The digit we are rounding to is the 5. The next digit is 7, which is more than 5, so we round up and increase the 5 by 1 to get 6. Answer: 6.
Round 2.5 to the nearest integer.	The digit we are rounding to is the 2. The next digit is 5, which is equal to 5, so we round up and increase the 2 by 1 to get 3. Answer: 3.
Round 9.99 to the nearest integer.	The digit we are rounding to is the 9 (units). The next digit is 9, which is more than 5, so we round up. The 9 becomes 10, so we set the units place to 0 and increase the tens place by 1 (which is also 9) to get 10. Answer: 10.
Round 0.49 to the nearest integer.	The digit we are rounding to is the 0. The next digit is 4, which is less than 5, so we round down and keep the 0 the same. Answer: 0.
How should you round 0.49 to avoid a common mistake?	Always look directly at the digit after the decimal point (4) and round down to 0; do not round 0.49 to 0.5 first (which would then round to 1). Don’t try to round in stages.
Round 999.50 to the nearest integer.	The digit we are rounding to is the last 9 (units). The next digit is 5, so we round up. The 9 becomes 10, set units to 0 and increase tens (9) to 10; repeat for hundreds place, resulting in 1000. Answer: 1000.