Converting fractions, decimals, and percents cheat sheet
Before we get started
The three basic ways to show values are with fractions, decimals, and percents. We use
these forms because many times values are not a complete whole number and have to be
shown as a part of a whole number.
Things people forget about fractions 4.5% = .045 12 = 12 7% = .07
1
We are going to start with things that you have to know.
.12
After the decimal, the 1 is in the tenths spot and the 2 is in the hundredths spot. This is
read as twelve hundredths. Since this sounds like 12 over 100, it can also be written as:
12
100
Since any percent is written as: number the fraction 12 is really just 12%
100
100
The next thing that you need to remember is the following symbol.
---------------------
D
2
P
-------------------This symbol will come in handy when converting from decimals to percents and percents
to decimals. The arrows stand for which direction you need to move the decimal to
convert the numbers. The rule that you have to remember will be the decimal in a whole
number goes behind the whole number. In other words, if you don’t see a decimal it
goes behind the number.
12.85 converts to 1285% because the decimal moves 2 times to the right.
33% converts to .33 because the decimal must be placed behind the last three 33. and
moved two times to the left .33
To convert from percent to fractions
This is much easier as long as you can remember that all fractions and percents can be
written as a number over one hundred.
15
100
=
15%
To convert fractions to decimals
You have to divide the bottom number into the top number. You will then end up with a
decimal.
___
4
5) 4
5
Since 5 cannot divide into 4 evenly, you have to add a decimal and a zero. (don’t forget
to bring the decimal up into the answer). I have used an x for a placeholder, the answer is
.8
_x.8
5) 4.0
-4 0
0
4
5
=
.8
To convert decimals to fractions
This is where you need to learn how to read decimals.
Since .8 is read as “eight tenths,” it is written how it sounds- 8
10
Many of these fractions can be reduced, so you need to do that if possible.
Converting fractions to percents
After dividing the bottom number into the top number, you get a decimal. Simply take
that answer and use the D2P to move the decimals around to convert the decimal into a
percent.
Don’t forget the order behind the decimals
. tenths, hundredths, thousandths, ten thousandths