# Round to a Given Number of Significant Figures

In this worksheet, students will practise rounding numbers to a given amount of significant figures.

Key stage:  KS 3

Curriculum topic:   Number

Curriculum subtopic:   Round/Approximate Numbers Appropriately

Difficulty level:

### QUESTION 1 of 10

In this worksheet, we will round to a given number of significant figures.

Look at the following examples.

The significant figures are shown in red.

The other zeros are there to make sure the size of the number is correct (e.g. 7000 not 7).

One significant figure:

7450 rounds to 7000

32 rounds to 30

35900 rounds to 40000

0.00448 rounds to 0.004

0.0000487 rounds to 0.00005

Two significant figures:

7450 rounds to 7500

32.5 rounds to 33

295 rounds to 300

35900 rounds to 36000

0.00448 rounds to 0.0045

0.0000401 rounds to 0.000040

Three significant figures:

7450 rounds to 7450

32.99 rounds to 33.0

35910 rounds to 35900

35990 rounds to 36000

0.004487 rounds to 0.00449

0.00004895 rounds to 0.0000490

Now let's consolidate your understanding by attacking some questions.

Over to you.

Round the following number to 1 significant figure.

275

Round the following number to 1 significant figure.

0.06524

Round the following number to 1 significant figure.

164

Round the following number to 1 significant figure.

0.024562

0.02

0.2

0.03

0.025

What is the following number rounded to 2 significant figures?

0.02572

0.02

0.2

0.03

0.025

Round the following number to 2 significant figures.

1244

Round the following number to 2 significant figures.

0.05254

0.05250

0.053

0.0531

0.0500

Round the following number to 2 significant figures.

0.0005478

0.05250

0.053

0.0531

0.0500

Round the following number to 3 significant figures.

83659

83700

83660

83000

80000

Round the following number to 3 significant figures.

0.0073568

• Question 1

Round the following number to 1 significant figure.

275

300
EDDIE SAYS
275 rounds up to 300. As we're rounding to 1 significant figure onto the first number is relevant, the second and third digit remain as zeros.
• Question 2

Round the following number to 1 significant figure.

0.06524

0.07
EDDIE SAYS
0.065 would round up to 0.07. Strong start if you spotted that, let's push on.
• Question 3

Round the following number to 1 significant figure.

164

200
EDDIE SAYS
164 rounds up to 200, because it is closer to 200 than 100. Also, as we're rounding to one decimal point the second and third digits are changed to zero.
• Question 4

Round the following number to 1 significant figure.

0.024562

0.02
EDDIE SAYS
0.024562 rounds down to 0.02, because the next significant figure - 4 - is less than the number 5. Hopefully, you're beginning to feel more confident, maths-whiz!
• Question 5

What is the following number rounded to 2 significant figures?

0.02572

EDDIE SAYS
Here, we take into consideration the number 7, which is the 3rd significant figure. As 7 is greater than 5, we round the number up to 0.026. Don't worry if you struggled with this one as there were more numbers to take into consideration. We will practise some more together.
• Question 6

Round the following number to 2 significant figures.

1244

1200
EDDIE SAYS
1244 is closer to 1200 than 1300, therefore we round down. As we are rounding to two significant figures we take into account both the '1' and '2' and the remaining numbers become zeros.
• Question 7

Round the following number to 2 significant figures.

0.05254

0.053
EDDIE SAYS
In this instance, we round up because the 3rd significant figure is 5. So, the answer is 0.053.
• Question 8

Round the following number to 2 significant figures.

0.0005478

EDDIE SAYS
Again, we have rounded up because the number after the 2nd significant figure is greater than five. Phew, that was a challenge! Don't worry if you found this tricky as it was a particularly small number you were dealing with, you still approach the question in the same way.
• Question 9

Round the following number to 3 significant figures.

83659

83700
EDDIE SAYS
Again, we round up here because 83659 is closer to 83700 than 83600. As we're rounding to 3 significant figures, the 4th and 5th digits are changed to zeros.
• Question 10

Round the following number to 3 significant figures.

0.0073568

0.00736
EDDIE SAYS
The answer here is 0.00736, because the 4th significant figure is higher than five. Great focus, that's another activity completed. Why not tackle another one so that you feel super confident?
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