What you need to know

Things to remember:

  • When rounding we look at the number to the right, so we look at the tenths when rounding to the nearest whole number.
  • If the tenths are 4 or less, the units stay the same and the tenths become 0.
  • If the tenths are 5 or more, the units go up by 1 and the tenths become 0.

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

So, how do we round numbers with decimals to the nearest whole number? Well, we do them in in the same way, we just look at the tenths.

Round 24.8 to the nearest whole number.

Step 1: Find the units.

24.8

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

24.8

Step 3: Round the units.

We have an 8, so the 4 is going to increase by 1 to make 5.

25.0

Step 4: Remove the decimal

25

So, 24.8 rounded to the nearest whole number is 25.

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

Round 3.4 to the nearest whole number.

Step 1: Find the units.

3.4

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

3.4

Step 3: Round the units.

We have a 4, so the 3 stays the same.

3.0

Step 4: Remove the decimal

3

So, 3.4 rounded to the nearest whole number is 3.

So, if the tenths are 5 or more the units go up by 1, but if the tenths are 4 or less, the units stay the same.

Here are some more examples of rounding to the nearest whole number:

Number           Rounded

13.4                  13

25.2                  25

44.8                  45

23.9                  24

Example Questions

Question 1: Round 63.6 to the nearest whole number.

Answer

Step 1: Find the units.

 

63.6

 

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

 

63.6

 

Step 3: Round the units.

 

We have a 6, so the 3 is going to increase by 1 to make 4.

 

64.0

 

Step 4: Remove the decimal

 

64

 

So, 63.6 rounded to the nearest whole number is 64.

Question 2: Round 18.1 to the nearest whole number.

Answer

Step 1: Find the units.

 

18.1

 

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

 

18.1

 

Step 3: Round the units.

 

We have a 1, so the 8 is going to stay the same.

 

18.0

 

Step 4: Remove the decimal

 

18

 

So, 18.1 rounded to the nearest whole number is 18.