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Compare 1/6 and 0.17

Step by step, with the reason for every step · Ordering mixed numbers and repeating decimals · Foundations

Step by step

The question

Question: compare 1/6 and 0.17.

16 and 0.17

1 Write it as a decimal

To compare, we write every number the same way: as a decimal.

The bottom 6 does not go into 10, 100 or 1000.

So we divide: 1 divided by 6, one digit at a time.

= 16 = 1 ÷ 6 = 0.166…

10 divided by 6 is 1, with 4 left.

40 divided by 6 is 6, with 4 left.

4 left again: the 6 repeats for ever.

So 1/6 is 0.166….

10 ÷ 6 = 1, 4 left
40 ÷ 6 = 6, 4 left: the 6 repeats

2 Same number of digits

Zeros at the end of a decimal do not change it: 0.17 is the same as 0.170.

A repeating decimal goes on for ever, so we can write as many of its digits as we need.

So we give every number 3 digits after the point.

= 0.166…, 0.170

3 Compare

Now both have 3 digits after the point.

So we can forget the point and compare them like whole numbers: 166 < 170.

= 0.166… < 0.170
166 < 170

4 Write the answer

Now with the numbers as they were given: 1/6 < 0.17.

1/6 is less than 0.17.

= 16 < 0.17

5 Check

Let's check on a number line.

Smaller numbers are further to the left.

We put a dot for each number.

From left to right: 1/6, 0.17.

The same order.

So the answer is right!

left to right: same order

Let's look back.

First: write it as a decimal.

Then: same number of digits.

Then: compare.

Then: write the answer.

Last: check.

Answer
= 16 < 0.17

Your turn

Try this one yourself, then check:

16 and 0.28
Show the answer
16 < 0.28

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