How To
What is a possible method for finding the LCM of a set of numbers?
Possible answers: use a number line, use a list, use prime factorization
What does LCM stand for?
Least Common Multiple
3/10 + 2/5 =
7/10
3/7 • 4/9 =
4/21
7/8 ÷ 2 =
7/16
When adding/subtracting fractions & mixed numbers, you must find ____________________.
Common denominators
What is the LCM of 6 and 4?
12
1 7/10 + 3 3/4 =
5 9/20
1 3/8 • 6/11 =
3/4
4/5 ÷ 3/4 =
16/15 or 1 1/15
Before multiplying or dividing, do you:
a. Find common denominators OR
b. Convert mixed numbers to improper fractions?
B. Convert to improper fractions
What is the LCM of 2, 7, and 42?
42
2/3 - 3/8 =
7/24
2 1/4 • 2 2/3 =
6
3 1/8 ÷ 1 1/4 =
2 1/2 or 5/2
Which operation requires the phrase “leave it, change it, flip it” to find the answer because you have to change the operation and flip the 2nd fraction?
Dividing
What is the LCM of 4, 8, and 10
40
1 1/12 + 2 2/3 =
3 3/4
7/12 • 14 =
49/6 or 8 1/6
3/8 ÷ 3 =
1/8
When you regroup a mixed number to subtract from it, how do you know what to add to the numerator?
For example, if you were to regroup 5 1/6?
You add the denominator, so in the example you would add 6 and get 4 7/6
What is the LCM of 9, 15, and 11?
495
4 1/9 - 2 4/9 =
1 2/3
Solve 3r = 9/10
R = 3/10
4 ÷ 1 3/5 =
2 1/2