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Write 0.2333... as a fraction

Step by step, with the reason for every step · Repeating decimals to fractions · Foundations

Step by step

The question

Question: write 0.2333 repeating as a fraction.

0.2333…

Look at the digits.

2 comes once.

Then 3 repeats for ever.

2 once, then 3 for ever

1 Call it x

We do not know the fraction yet.

So we call the number x: x = 0.2333 repeating.

x = 0.2333…

Careful!

It is not 23/100.

That is 0.23, which stops.

Ours goes on for ever.

Careful: not 0.2333… = 23100 ✗

2 Move the point

First we move the point past the 2, which does not repeat.

Times 10 moves the point 1 place to the right.

We do it to both sides, so they stay equal.

10x = 2.333…
× 10: point moves 1 place

Then one block more: times 100 moves it 2 places.

Now both numbers have the same tail after the point.

100x = 23.333…
× 100: point moves 2 places

3 Take away

Now we take the smaller one away from the bigger one.

Both sides, so they stay equal.

100x − 10x = 23.333… − 2.333…

After the point, both go on with 3 for ever.

The tails are exactly the same, so they make zero.

Cross them out.

100x minus 10x is 90x.

23 minus 2 is 21.

90x = 21

4 Remove the 90

90x means 90 times x.

We want just x.

To remove times 90, we divide by 90.

90x90 = 2190

90 divided by 90 is 1.

So just x is left.

21 and 90 can both be divided by 3.

We can make 21/90 simpler.

It is the same as 7/30.

21 ÷ 390 ÷ 3 = 730

So x = 7/30.

x = 730

So 0.2333 repeating is 7/30.

5 Check

Let's check: 7 divided by 30.

We get 0.2333, and the digits go on the same way.

That is 0.2333 repeating.

So the answer is right!

7 ÷ 30 = 0.2333…

Let's look back.

First: call it x.

Then: move the point.

Then: take away.

Then: remove the 90.

Last: check.

Answer
x = 730

Your turn

Try this one yourself, then check:

Write 0.2666…
Show the answer
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