34
FRACTION - a number that shows parts or pieces of a whole
denominator
numerator
74
IMPROPER FRACTION - when the number on top is bigger than the number on the bottom.
34
MIXED NUMBER - a number that shows wholes and fractions
1
Adding Fractions
34
25+
Step 1: Find a common denominator
The LCM of
4 and 5 is 20.
Step 2: Find equivalent fractions with the common denominator
Adding Fractions
34
25+
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
5 x x 4
The LCM of
4 and 5 is 20.
Adding Fractions
34
25+
Step 1: Find a common denominator
What you do to the bottom
you have to do to the top.
Step 2: Find equivalent fractions with the common denominator
5 x
5 x
x 4
x 4
Adding Fractions
1520
820+
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
Step 3: Add the numerators. Keep the same denominator.
What you do to the bottom
you have to do to the top.
Adding Fractions
1520
820+
Step 1: Find a common denominator
15 + 8 = 23
Step 2: Find equivalent fractions with the common denominator
Step 3: Add the numerators. Keep the same denominator.
Adding Fractions
1520
820+
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
Step 3: Add the numerators. Keep the same denominator.
= 2320
Adding Fractions
Step 1: Find a common denominator
Change impropers to
mixed #s
Step 2: Find equivalent fractions with the common denominator
Step 3: Add the numerators. Keep the same denominator.
Step 4: Simplify if necessary
1520
820+ = 23
20
Adding Fractions
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
Step 3: Add the numerators. Keep the same denominator.
Step 4: Simplify if necessary
1520
820+ = 23
20 = 3201
20 can go into 23 1 time.
There is a remainder of 3.
Subtracting Fractions
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
12
16 - The LCM for
2 and 6 is 12
Subtracting Fractions
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
6 12
212- The LCM for
2 and 6 is 12
Step 3: Subtract the numerators. Keep the same denominator.
Subtracting Fractions
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
6 - 2 = 4
Step 3: Subtract the numerators. Keep the same denominator.
= 412
6 12
212-
Subtracting Fractions
Step 1: Find a common denominator
Step 2: Find equivalent fractions with the common denominator
4 and 12 share a common factor of 4
Step 3: Subtract the numerators. Keep the same denominator.
Step 4: Simplify if necessary
//
4
4
= 13= 4
126 2
12-12
Multiplying Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
Oh good!
=4 6x73
Step 1: Multiply the numerators.
Multiplying Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
4 x 3 = 12
=4 6x73
Step 1: Multiply the numerators.
Step 2: Multiply the denominators
12
Multiplying Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
7 x 6 = 42
=4 6x73
Step 1: Multiply the numerators.
Step 2: Multiply the denominators
1242
Step 3: Simplify if necessary
Multiplying Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
The GCF for 12 and 42 is 6
=4 6x73
Step 1: Multiply the numerators.
Step 2: Multiply the denominators
1242
Step 3: Simplify if necessary
6
6// 2
7=
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
Do I need a common
denominator?13/22
Step 1: Find the reciprocal of the second fraction
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
FLIP THE SECOND ONE!1
3/22
Step 1: Find the reciprocal of the second fraction
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
12/23
Step 1: Find the reciprocal of the second fraction
Step 2: Change division to multiplication
FLIP THE SECOND ONE!
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
/ to X 12/23
Step 1: Find the reciprocal of the second fraction
Step 2: Change division to multiplication
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
1223
Step 1: Find the reciprocal of the second fraction
Step 2: Change division to multiplication
x
Step 3: Multiply and simplify if necessary
/ to X
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
1 x 3
and
2 x 2 1223
Step 1: Find the reciprocal of the second fraction
Step 2: Change division to multiplication
x
Step 3: Multiply and simplify if necessary
= 34
Dividing Fractions
YOU DO NOT NEED A COMMON DENOMINATOR
EASY!!! 1223
Step 1: Find the reciprocal of the second fraction
Step 2: Change division to multiplication
x
Step 3: Multiply and simplify if necessary
= 34
Special Situations
• Adding and subtracting mixed numbers: just add or subtract fractions, then wholes.
• Subtracting mixed numbers when the first fraction part is smaller than the second: change to improper fractions.
• Multiplying and dividing mixed numbers and wholes: change to improper fractions