What you need to know

Things to remember:

  • Figure out the two nearest whole numbers
  • Look at the first digit to the right of the decimal point
  • Decide whether to round up or down

Let’s remind ourselves how we round to the nearest 10.

We find the tens and then look to the right.
If the units are 4 or less, the tens stay the same and the units become 0.
If the units are 5 or more, then tens go up by 1 and the units become 0.

Number           Rounded

22                    20

31                    30

65                    70

38                    49

Round 2.64 to the nearest whole number.

If we put 2.64 on a number line, we would see that it is between 2 and 3, so we need to see if it is nearer to 2 or to 3. We can find out which one we round to by using our usual steps.

Step 1: Find the number we’re rounding to (the units).

2.64

Step 2: Look at the number to the right (the tenths)

2.64

 

Step 3: Round the tenths.

We have a 6, so the 2 is going to increase by 1 to make 3.

3.00

Step 4: Remove the 0s after the decimal

3

So, 2.64 rounded to the nearest whole number is 3.

We do the same when the tenths are less than 5, but the units don’t change.

Example Questions

Question 1: Round 4.55 to the nearest whole number.

Answer

Step 1: Find the number we’re rounding to (the units).

 

4.55

 

Step 2: Look at the number to the right (the tenths)

 

4.55

 

Step 3: Round the tenths.

 

We have a 5, so the 4 is going to increase by 1 to make 5.

 

5.00

 

Step 4: Remove the 0s after the decimal

 

5

 

So, 4.55 rounded to the nearest whole number is 5.

Question 2: Round 0.34 to the nearest whole number.

Answer

Step 1: Find the number we’re rounding to (the units).

 

 

0.34

 

Step 2: Look at the number to the right (the tenths)

 

0.34

 

 

Step 3: Round the tenths.

 

We have a 3, so the 0 is going to stay the same.

 

0.00

 

Step 4: Remove the 0s after the decimal.

 

0

 

So, 0.34 rounded to the nearest whole number is 0.