Find LCM
Write multiples and find least common multiple of 6 and 8.
6: 12, 18, 24, 30, 36
8:16, 24, 32, 40, 48
LCM: 24
Subtract: 8 / 11 - 3 / 11
= 5 / 11
Multiply: 9 / 20 of 5 / 21 = ?
3 / 28
(3 + 4 * 6) ÷ 9 = ?
= (3 + 24) ÷ 9
= 27 ÷ 9
= 3
Marvin has 3 / 4 yard of material. He uses 1 / 4 to cover a chair. How many yards are left?
3 / 4 - 1 / 4
= 3 - 1 / 4
= 1 / 2 yard
Write multiples and find least common multiple of 15 and 20.
15: 15, 30, 45, 60, 75
20: 20, 40, 60, 80, 100
LCM: 60
Add: -27 / 43 + 15 / 43
Divide: 3 / 5 ÷ 4 / 11 = ?
20 / 33
9 ÷ 3 + 2 * (9 + 10) - 8 + 4 * 3 = ?
= 9 ÷ 3 + 2 * (19) - 8 + 4 * 3
= 9 ÷ 3 + 38 - 8 + 4 * 3
= 3 + 38 - 8 + 12
= 41 - 8 + 12
= 33 + 12
= 45
A recipe needs 3/4 teaspoon black pepper and 1/4 teaspoon red pepper. How much more black pepper does the recipe need?
= 3 / 4 - 1 / 4
= 2 / 4
= 1 / 2
Build LCM for 8, 12, and 42.
8: 2 * 2 * 2 or 23
12: 2 * 2 * 3 or 22 * 3
42: 2 * 3 * 7
LCM: 23 * 3 * 7 = 8 * 3 * 7 = 168
Find LCD then Add: -5 / 7 + 5 / 8
-5 / 56
Divide: -21x2 / 50 ÷ 7x4 / 20
- 5x2 / 6
10 ÷ (3 + 2) * 4 + 52 + 6 - 9 = ?
= 10 ÷ (5) * 4 + 52 + 6 - 9
= 10 ÷ 5 * 4 + 25 + 6 - 9
= 2 * 4 + 25 + 6 - 9
= 8 + 25 + 6 - 9
= 33 + 6 - 9
= 39 - 9
= 30
Mary is preparing a final exam. She studied 3/2 hours on Friday, 6/4 hours on Saturday, and 2/3 hours on Sunday. How many hours did she study over the weekend (all 3 days)?
3 / 2 + 5 / 4 + 2 / 3
= 18 / 12 + 15 / 12 + 8 / 12
= 41 / 12
= 3 5 / 12
Approx: 4 hours
Build LCM for 6x, 8x.
6x: 2 * 3 * x
8x: 2 * 2 * 2 * x or 23 * x
LCM: 23 * 3 * x = 8 * 3 * x = 24x
Add Mixed Numbers: 5 14 / 15 + 10 3 / 10 = ?
LCD: 30
Answer in an improper fraction for: 15 37 / 30
Answer in a proper fraction form: 16 7 / 30
Multiply Mixed Numbers: 4 7 / 12 * 2 8 / 15 = ?
Answer in an improper fraction form: 209 / 18
Answer in a proper fraction form: 11 11 / 18
Order of Operations with Mixed Numbers:
1 2 / 3 ÷ 6 * (3 / 10) = ?
= 5 / 3 ÷ 6 / 1 * 3 / 10
= 5 / 3 * 1 / 6 * 3 / 10
= 5 / 18 * 3 / 10
= 1 / 12
What is one-third of three-fourths?
= 1 / 3 × 3 / 4
= 3 / 12
= 1 / 4
Build LCM for 14x and 7x2.
14x: 2 * 7 * x
7x2: 7 * x * x or 7x2
LCM: 2 * 7 * x2 = 14x2
Subtract Mixed Numbers: 5 2 / 5 - 3 7 / 8 = ?
LCD: 40
Answer: 1 21 / 40
Divide Mixed Numbers: 2 1 / 3 ÷ 3 2 / 5 = ?
Answer: 35 / 51
Order of Operations with Mixed Numbers:
2 / 3 + (2 2 / 5 - 1 2 / 3)2 = ?
= 2 / 3 + (12 / 5 - 5 / 3)2
LCD: 15= 2 / 3 + (36 / 15 - 25 / 15)2
= 2 / 3 + (11 / 15)2
= 2 / 3 + 121 / 225
LCD: 225
= 150 / 225 + 121 / 225
= 271 / 225 or 1 46 / 225
How many halves are there in six-fourths?
= 6 / 4 ÷ 1 / 2
= 6 / 4 × 2 / 1
= 12/4
= 3