Step by step
The question
Question: put 0.125, 1/10, 0.15, −1/8 in order, from smallest to largest.
1 Write each as a decimal
To compare, we write every number the same way: as a decimal.
1 tenths is 0.1.
So 1/10 is 0.1.
8 times 125 is 1000.
So we multiply the top and the bottom by 125.
125 thousandths is 0.125.
The minus sign stays in front: −0.125.
2 Same number of digits
Zeros at the end of a decimal do not change it: 0.1 is the same as 0.100.
So we give every number 3 digits after the point.
3 Compare
Now they all have 3 digits after the point.
So we can forget the point and compare them like whole numbers: 100 < 125 < 150.
Careful!
More digits does not mean bigger.
Compare 0.125 with 0.150.
Negative numbers are smaller than every positive number.
So they come first.
4 Write the answer
Now we write the numbers as they were given, in the same order: −1/8, 1/10, 0.125, 0.15.
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: −1/8, 1/10, 0.125, 0.15.
The same order.
So the answer is right!
Let's look back.
First: write each as a decimal.
Then: same number of digits.
Then: compare.
Then: write the answer.
Last: check.