Order the set of numbers from least to greatest.

1/5, 25%, 0.28, 0.04

0.04, 1/5, 0.28, 25%

To order the set of numbers from least to greatest, we need to convert all the numbers to the same format.

0.04 is already in decimal form.

1/5 can be converted to a decimal by dividing 1 by 5, which gives us 0.2.

25% can be converted to a decimal by dividing 25 by 100, which gives us 0.25.

0.28 is already in decimal form.

Now we can compare the numbers:

0.04 < 0.2 < 0.25 < 0.28

So the set of numbers from least to greatest is:

0.04, 1/5, 25%, 0.28