Round 81,340 to 2 significant figures Step by Step

Step by step

The question

Question: round 81,340 to 2 significant figures.

Round 81,340 to 2 significant figures

1 Find the first significant figure

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

In 81,340, it is 8.

= 81,340

significant figures: counted from

the first digit that is not 0

2 Count the figures

We count 2 figures from there: 8, 1.

The 2nd figure, 1, is in the thousands place.

So we round to the nearest thousand.

= 2nd figure 1 → the thousands place

3 Look at the next digit

Now we look at the next digit to the right.

It is 3.

5 or more: we round up.

4 or less: we round down.

3 is 4 or less, so we round down.

= 3 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

81,340 is closer to 81,000.

5 Keep the size

The places after the 2nd figure become 0.

The zeros keep the size: 81,000 is close to 81,340.

= 81,340 ≈ 81,000

Careful!

81 is much smaller than 81,340.

The zeros keep the number the right size.

Careful: not 81,340 ≈ 81 ✗

So 81,340 to 2 significant figures is 81,000.

6 Check

Let's check.

81,000 has 2 significant figures: 8, 1.

81,000: figures 8, 1 → 2 s.f.

And it is the same size as 81,340: 5 digits before the point.

So the answer is right!

81,340 and 81,000: both 5 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