Round 254.7 to 2 significant figures Step by Step

Step by step

The question

Question: round 254.7 to 2 significant figures.

Round 254.7 to 2 significant figures

1 Find the first significant figure

The first significant figure is the first digit that is not 0.

In 254.7, it is 2.

= 254.7

significant figures: counted from

the first digit that is not 0

2 Count the figures

We count 2 figures from there: 2, 5.

The 2nd figure, 5, is in the tens place.

So we round to the nearest ten.

= 2nd figure 5 → the tens place

3 Look at the next digit

Now we look at the next digit to the right.

It is 4.

5 or more: we round up.

4 or less: we round down.

4 is 4 or less, so we round down.

= 4 is 4 or less → round down

5 or more → up: digit + 1

4 or less → down: digit stays

4 See it on a number line

254.7 is closer to 250.

5 Keep the size

The places after the 2nd figure become 0.

The zeros keep the size: 250 is close to 254.7.

= 254.7 ≈ 250

Careful!

25 is much smaller than 254.7.

The zeros keep the number the right size.

Careful: not 254.7 ≈ 25 ✗

So 254.7 to 2 significant figures is 250.

6 Check

Let's check.

250 has 2 significant figures: 2, 5.

250: figures 2, 5 → 2 s.f.

And it is the same size as 254.7: 3 digits before the point.

So the answer is right!

254.7 and 250: both 3 digits before the point

Let's look back.

First: find the first significant figure.

Then: count the figures.

Then: look at the next digit.

Then: see it on a number line.

Then: keep the size.

Last: check.

Answer