Fractions
Vocabulary
Numerator: The top number in a fraction.
The number of parts.
Denominator: The bottom number in a fraction.
How many equal parts something is divided into.
2
Numerator
3
Denominator
Vocabulary
Least Common Multiple (LCM): The smallest
multiple shared between a group of numbers
Least Common Denominator (LCD): The smallest
multiple shared between a group of denominators
Finding the Least common multiple or denominator
1. List the multiples of your first number
a. EXAMPLE
3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36,
2. List the multiples of your second number
a. EXAMPLE
7: 7, 14, 21, 28
3. Find the SMALLEST number that is shared
Find the Least Common Multiple. Type the Answer in the
center column.
Number 1 Least Common Multiple Number 2
2
3
7
56
8
5
44
14
20
22
13
31
Adding Fractions
If the denominators are
the same. Add the
numerators.
Simplify if needed.
2
3
5
8
8
8
Adding Fractions with different denominators
Step 1: Find the LCD
Problem
2
1
8
3
Multiples of 8
8, 16, 24, 32,
Multiples of 3
3, 6, 9, 12, 15, 18, 21, 24
Step 2: Multiply the Fractions
2
3
8
3 24
6
LCD is 24
Step 3: Add the new
fractions
6
8
14
24
24
24
Step 4: Simplify
1
8
8
14
2
7
3
8
24
24
2
12
PROOF
2
8
6
24
8
24
1
3
Subtracting Fractions
Works the same as adding, just subtract
If the denominators are equal then subtract the
numerators
If the denominators are different then find the LCD,
multiply the numerator and denominator, then
subtract
Simplify if needed
Guided practice
2
1
6
2
3
5
8
8
3
6
7
3
12
12
8
6