What you need to know

Things to remember:

  • When rounding to 1 decimal place we look at the hundredths to see how to round.
  • If the hundredths are 4 or less, the tenths stay the same and the hundredths become 0.
  • If the hundredths are 5 or more, the tenths go up by 1 and the hundredths 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, let’s look at how we round to 1 decimal place.

Round 2.36 to 1 decimal place.

We do this using the same step as we have done previously.

Step 1: Find first decimal place (the tenths).

2.36

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

2.36

 

Step 3: Round the tenths.

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

2.40

Step 4: Remove the 0

2.4

So, 2.36 rounded to 1 decimal place is 2.4.

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

Example Questions

Question 1: Round 5.89 to 1 decimal place.

Answer

Step 1: Find first decimal place (the tenths).

 

5.89

 

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

 

5.89

 

Step 3: Round the tenths.

 

We have a 9, so the 8 is going to increase by 1 to make 9.

 

5.90

 

Step 4: Remove the 0

 

5.9

 

So, 5.89 rounded to 1 decimal place is 5.9.

Question 2: Round 6.23 to 1 decimal place.

Answer

Step 1: Find first decimal place (the tenths).

 

6.23

 

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

 

6.23

 

Step 3: Round the tenths.

 

We have a 3, so the 2 is going to stay the same.

 

6.20

 

Step 4: Remove the 0

 

6.2

 

So, 6.23 rounded to 1 decimal place is 6.2.