1. Fractions, Decimals, & Percents
Users Guide to
Fractions, Decimals, & Percents
By: Mrs. Hubbard

2. Fractions Denominator- the number on the bottom of a fraction
*Represents how many equal pieces something is being cut into
Numerator- the number on the top
*Represents the number of equal pieces

3. Example: two fifths 2/5

4. Equivalent Fractions
Equivalent Fractions are fractions that are equal to each other.
For instance: 1/2 = 2/4
To find equivalent fractions, just multiply the numerator and denominator by the same number.
Example: 1 x 2= 2
2 x 2= 4

5. Simplifying Fractions
Simplifying Fractions means to change the fractions into their simplest form
Example: 5/10 = 1/2
You can make this change easily by looking at the factors of both the numerator and denominator.
Factors of 5: 1, 5
Factors of 10: 1, 2, 5, 10

6. Simplifying Fractions cont…
Factors of 5: 1, 5
Factors of 10: 1, 2, 5, 10
The common factors between both numbers are one and five. Five is the Greatest. So it is the Greatest Common Factor. Most mathematicians call this the GCF.
Find out how many times the GCF goes into both the numerator and denominator.
5 goes into 5, 1 time
5 goes into 10, 2 times
therefore…. 5/10 = 1/2

7. Adding & Subtracting Fractions
When adding and subtracting fractions, you must first have the same denominators for both fractions.
Example: 1/4 + 2/4
Keep the denominator the same- add or subtract the numerators.
1/4 + 2/4 = ¾
(again, the denominator stays the same, the numerators get added together.)

8. Common Denominators
Before you can add fractions, you must make the denominators the same. This is called having common denominators.
You can make common denominators by looking at the multiples of both denominators. The smallest common multiple (least common multiple-LCM) becomes your new denominator.

9. Example
1/5 + 2/3
Look at the denominators and find the LCM (least common multiple)
Multiples of 5: 5, 10, 15, 20, 25, 30…
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30…
15 is the smallest multiple that both numbers have in common; therefore, that is the number that should be used. Although, 30 and any other common multiples will also work.

10. Cool Math Site
Below is a website that will calculate the Least Common Multiple for you…
You can use it to check your answers.
LCM

11. Example continued
1/ /3
10/15
3/15 +
The answer is 13/15.

12. ….. Answer
1/5 + 2/3 =
1/5 = 3/15
2/3 = 10/15
3/ /15 =
13/15

13. Check out this video about how to find Common Denominators

14. Multiplying Fractions
When multiplying fractions… or should I say when finding the product of fractions…
You simply multiply across.
Step 1- Multiply the Numerators
Step 2- Multiply the Denominators
Step 3- Simplify
*Please note that in most cases, you must simplify the fraction after multiplying.

15. Example continued… 2/5 x 3/8 = (2 x 3) / (5 x 8) = 6/40 6/40 = 3/20

16. Decimals .55 means … Tenths Hundredths Thousandths Ten-thousandths
Hundred- thousandths
Millionths
Think about place value and think about money
.55 means …
Fifty-five hundredths Or
Five tenths plus five hundredths

17. 0.75 = ¾ = 75/100 = 75%

18. Percents Percent form tells how many per every hundred. 50% : 50/100
50% : 50/100
Also equal to ½ or
100/200 or 200/400

19. Benchmark Fractions
These are the fractions that are the most commonly used. Memorize these benchmark fractions and their percent and decimal equivalents to make working with fractions easier.
50%
0.50
1/3
33%
0.333
25%
0.25
1/5
20%
0.20
1/6
16.7%
0.167
1/8
12.5%
0.125
1/10
10%
0.10
2/3
67%
0.667
75%
0.75