Steply

Order 2 1/4, 2.3, 2 1/5 from smallest to largest

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

Step by step

The question

Question: put 2 and 1/4, 2.3, 2 and 1/5 in order, from smallest to largest.

214, 2.3, 215

1 Write each as a decimal

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

2 and 1/4 means 2 plus 1/4.

= 214 = 2 + 14 = 2 + 0.25 = 2.25

4 times 25 is 100, so we multiply the top and the bottom by 25.

1/4 is 25 hundredths: 0.25.

So 2 and 1/4 is 2.25.

1 × 254 × 25 = 25100 = 0.25

Careful!

The 1 and the 4 are a fraction, not digits after the point.

1/4 is 0.25.

Careful: not 214 = 2.14 ✗

2 and 1/5 means 2 plus 1/5.

= 215 = 2 + 15 = 2 + 0.2 = 2.2

5 times 2 is 10, so we multiply the top and the bottom by 2.

1/5 is 2 tenths: 0.2.

So 2 and 1/5 is 2.2.

1 × 25 × 2 = 210 = 0.2

2 Same number of digits

Zeros at the end of a decimal do not change it: 2.3 is the same as 2.30.

So we give every number 2 digits after the point.

= 2.25, 2.30, 2.20

3 Compare

Now they all have 2 digits after the point.

So we can forget the point and compare them like whole numbers: 220 < 225 < 230.

= 2.20 < 2.25 < 2.30
220 < 225 < 230

4 Write the answer

Now we write the numbers as they were given, in the same order: 2 and 1/5, 2 and 1/4, 2.3.

= 215 < 214 < 2.3

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: 2 and 1/5, 2 and 1/4, 2.3.

The same order.

So the answer is right!

left to right: same order

Let's look back.

First: write each as a decimal.

Then: same number of digits.

Then: compare.

Then: write the answer.

Last: check.

Answer
= 215 < 214 < 2.3

Your turn

Try this one yourself, then check:

234, 2.8, 212
Show the answer
212 < 234 < 2.8

More from Ordering mixed numbers and repeating decimals

The whole lesson: Ordering mixed numbers and repeating decimals →