Round 5764 to 2 significant figures Easy

The question

Question: round 5764 to 2 significant figures.

1 Find the first significant figure

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

In 5764, it is 5.

2 Count the figures

We count 2 figures from there: 5, 7.

The 2nd figure, 7, is in the hundreds place.

So we round to the nearest hundred.

3 Look at the next digit

Now we look at the next digit to the right.

It is 6.

5 or more: we round up.

4 or less: we round down.

6 is 5 or more, so we round up.

4 See it on a number line

5764 is closer to 5800.

5 Keep the size

The places after the 2nd figure become 0.

The zeros keep the size: 5800 is close to 5764.

Careful!

58 is much smaller than 5764.

The zeros keep the number the right size.

So 5764 to 2 significant figures is 5800.

6 Check

Let's check.

5800 has 2 significant figures: 5, 8.

And it is the same size as 5764: 4 digits before the point.

So the answer is right!

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.

▶ Watch it solved

Round 0.004567 to 2 significant figures Medium

The question

Question: round 0.004567 to 2 significant figures.

1 Find the first significant figure

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

In 0.004567, it is 4.

The zeros in front only hold the place.

They are not counted.

2 Count the figures

We count 2 figures from there: 4, 5.

The 2nd figure, 5, is in the ten-thousandths place.

So we round to the nearest ten-thousandth.

3 Look at the next digit

Now we look at the next digit to the right.

It is 6.

5 or more: we round up.

4 or less: we round down.

6 is 5 or more, so we round up.

4 See it on a number line

0.004567 is closer to 0.0046.

5 Keep the size

We stop after the 2nd figure.

So 0.004567 is about 0.0046.

Careful!

The zeros in front are not counted.

But they stay in the answer.

They hold the place.

So 0.004567 to 2 significant figures is 0.0046.

6 Check

Let's check.

0.0046 has 2 significant figures: 4, 6.

And it is close to 0.004567.

So the answer is right!

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.

▶ Watch it solved

Estimate 41.3 × 9.79 ÷ 0.765 Harder

The question

Question: estimate 41.3 × 9.79 ÷ 0.765.

To estimate means to find about how big the answer is.

We make every number easy first.

1 Round to 1 significant figure

We round each number to 1 significant figure: only its first figure stays.

41.3: the first figure is 4.

The next digit is 1, 4 or less, so we round down: 40.

9.79: the first figure is 9.

The next digit is 7, 5 or more, so we round up: 10.

0.765: the first figure is 7.

The next digit is 6, 5 or more, so we round up: 0.8.

2 Work it out

So the answer is about 40 × 10 ÷ 0.8.

Now it is easy to work out.

Careful!

We changed the numbers.

So we write ≈, about, not =.

40 times 10 is 400.

400 divided by 0.8 is 500.

To divide by 0.8, we move the point in both numbers 1 place: 4000 divided by 8.

That is 500.

So the answer is about 500.

3 Check

Let's check with a calculator.

The exact answer is about 528.5.

That is close to 500.

So the estimate is good!

Let's look back.

First: round to 1 significant figure.

Then: work it out.

Last: check.

▶ Watch it solved