Steps
What is the first step when solving adding and subtracting fractions with unlike denominators?
Find the LCD
2 1
____ + ____ =
3 4
11
___
12
1 1
____ - ___ =
3 4
1
___
12
Jen runs 2 2/3 miles on Monday and another 4 4/12 miles on Thursday. How many miles did she run in all?
7 miles
What is a denominator?
The number below the line in a fraction.
What do I do if I cannot subtract because the fraction is larger on top? (See board for example)
Regroup
3 2
____ + ___ =
4 3
17
___
12
2 1
____ - ___ =
3 5
7
____
15
Jillian had 3 3/4 pounds of pasta. She cooked 1 1/2 pounds. How many pounds of pasta did she have left over?
2 1/4 pounds
What is a numerator?
The number above the line in a fraction.
Explain how to regroup
answers will vary
4 3
____ + ___ =
5 4
31
____
20
1 1
____ - ___ =
2 5
3
___
10
Dimitri read for 7 1/12 hours on Monday, 3 3/4 hours on Tuesday, and 6 4/8 hours on Wednesday. How many hours did he read in all?
17 1/3 hours
What does equivalent mean?
Equal in value or the same in value.
When simplifying a fraction, do you find the LCM or the GCF?
GCF
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.
When finding the LCD do you need to make a list of multiples or factors?
multiples Remember: to find the LCD we find the LCM
5 7
____ + ___ =
7 8
89
_____
56
5 1
____ - ___ =
7 3
8
___
21
2 2
4 ____ - 3 ___ =
6 3
12 2
_____ = _____
18 3
What is a common denominator?
When your denominators are the same value.