Steps- Fraction Model
What is the first step when solving adding and subtracting fractions with unlike denominators?
Model one each fraction on a different one whole block or .
2 1
____ + ____ =
3 4
11
___
12
1 1
____ - ___ =
3 4
1
___
12
3 2
2 ____ + ___ =
4 3
41
____
12
What is a denominator?
The number below the line in a fraction.
What is the second step when adding and subtracting fractions with unlike denominators?
Create equivalent fractions with like denominators.
3 2
____ + ___ =
4 3
17 /12 or 1 5/12
2 1
____ - ___ =
3 5
7
____
15
1 5
2 ____ + ___ =
4 6
74
______
24
What is a numerator?
The number above the line in a fraction.
What is the third step when adding and subtracting fractions with unlike denominators?
Add fractions with like denominators.
4 3
____ + ___ =
5 4
31/20 or 1 11/20
1 1
____ - ___ =
2 5
3
___
10
1 4
3 ____ + ___ =
4 5
81
____
20
What does equivalent mean?
Equal in value or the same in value.
What is the fourth step when adding and subtracting fractions with unlike denominators?
Simplify the fraction (If Needed).
6 5
____ + ___ =
7 6
71
_____
42
4 2
____ - ___ =
5 3
2
___
15
1 4
3 ____ - ___ =
5 6
76
____
30
What does simplify mean?
To reduce a fraction to it's simplest form.
How can we check that our answer is reasonable?
We can compare the fractions to the fraction 1/2 if it is less than 1 or compare the fractions to a whole number if larger than 1.
Mr. Kreider wants to paint two doors and several shutters. It takes 2 1/8 gallons of paint to coat each door and 1 3/5 gallons of paint to coat all of his shutters. If Mr. Kreider buys three 2-gallon cans of paint, does he have enough to complete the job?
Yes, because he will have 6 gallons in all and we have less than 6 being used.
Mr. Kreider wants to paint two doors and several shutters. It takes 2 1/8 gallons of paint to coat each door and 1 3/5 gallons of paint to coat all of his shutters. If Mr. Kreider buys three 2-gallon cans of paint, how much does he have left over?
Mr. Kreider will have 11/40.
2 2
4 ____ - 3 ___ =
6 3
12 2
_____ = _____
18 3
What is a common denominator?
When your denominators are the same value.