Adding fractions with unlike denominators
2/3 + 1/4
8/12 + 3/12 = 11/12
1/3 - 1/4
4/12 - 3/12 = 1/12
2 3/4 + 2/3
2 9/12 + 8/12 = 41/12 = 2 17/12
Simplified: 3 5/12
What is a denominator?
The number on the bottom of the fraction or the number below the line in the fraction
George ate 1/5 of the cake and Eleanor ate 2/3 of the cake. How much did they eat altogether?
They ate 13/15 of the cake.
3/4 + 2/3
9/12 + 8/12 = 17/12
Simplified: 1 5/12
2/3 - 1/5
10/15 - 3/15 = 7/15
2 1/4 + 5/6
2 3/12 + 10/12 = 2 13/12
Simplified: 3 1/12
What is a numerator?
The number on the top of the fraction or the number above the line in a fraction
Jim wrote 1/3 of the project and Jenny wrote 1/2 of the project. If Suzy has to do the rest, how much does she have to write?
Suzy has to write 1/6 of the project.
4/5 + 3/4
16/20 + 15/20 = 31/20
Simplified: 1 11/20
1/2 - 1/5
5/10 - 2/10 = 3/10
3 1/4 + 4/5
3 5/20 + 16/20 = 3 21/20
Simplified: 4 1/20
What does equivalent mean?
Equal in value or the same in value
If Sally spent 1/3 of her money on lotion, 1/8 of her money on makeup and 1/2 of her money on hair ties, what fraction of her money is left?
She has 1/24 of her money left.
6/7 + 5/6
36/42 + 35/42 = 71/42
Simplified: 1 29/42
4/5 - 2/3
12/15 - 10/15 = 2/15
Simplified: 1/5
3 1/5 - 2/3
3 3/15 - 10/15 = 2 18/15 - 10/15 =
2 8/15
What does simplify mean?
To reduce the fraction to its simplest form or the smallest form of a fraction
Patty bought 2 lbs of flour. She used 2/3 lb to make cookies, 3/5 lb to make pie and some pounds of flour to make brownies. When done, she had 2/15 lbs left. How much flour did she use to make brownies?
Patty used 9/15 lbs to make brownies.
5/7 + 7/8
40/56 + 49/56 = 89/56
Simplified: 1 33/56
5/7 - 1/3
15/21 - 7/21 = 8/21
4 2/6 - 3 2/3
1 2/6 - 2/3 = 1 2/6 - 4/6 = 8/6 - 4/6 = 4/6
Simplified: 2/3
What is a common denominator?
Shared number between both denominators
Ben sold 3/4 gallons of apple cider and Josh sold some too. Together they sold 1 5/12 gallons of cider. How much did they each sell? And who sold more?
Ben sold 9/12 or 3/4 and Josh sold 8/12 or 2/3. Ben sold more cider.