Estimation
What would you estimate 78 x 31?
80 x 30
Find a number between 20 and 30 that is exactly divisible by 12
Count by multiples. . . . 12, 24, 36
24 meets the criteria
What is the LCM of 2 and 3?
6
True or false - 2 is a common factor of 26 and 62.
True
Is 20 a common factor of 10 and 20?
No. The factors of 10 are (1, 2, 5, 10) and the factors of 20 are (1, 2, 4, 5, 10, 20)
A number rounded to the nearest 10 is 830. Find the greatest possible number.
_l i i
825 830 834
What is the sum of all of the factors of 8?
8 (1, 2, 4, 8)
1 + 2 + 4 + 8 = 15
What is the LCM of 5 and 7?
35
3 is a common factor of 13 and 19.
False - 13 and 19 are both prime.
What is the LCM of 2 and 5?
10
14 is a common factor of 39 and 63.
False . . . 14 x 3 = 42, 14 x 4 = 56 and 14 x 5 = 70
OR 39 (1, 3, 13, 39) and (1, 3, 7, 9, 21, 63)
What is the sum of all the factors of 35?
35 - (1, 5, 7, 35)
1 + 5 + 7 + 35 = 48
What is the LCM of 6 and 18?
18
6 is a common factor of 18 and 78. . . true or false?
True. . . 18 / 6 = 3 and 78 is divisible by 2 and 3 so it is divisible by 6.
What is the GCF of 5 and 15?
5 - (1, 5) and 15 - (1, 3, 5, 15)
5 is the GCF
What is the estimated quotient of 718 /6?
720 / 6 = 120
Find two prime numbers between 30 and 45.
31, 37, 41, or 43
What is the LCM of 4 and 8?
8
Find the product of 489 x 7
Estimate to check that your answer is correct.
489 x 7 - 3,423
Estimate: 400 x 7 = 2,800
What is the LCM of 2 and 14?
14
How would I solve the estimated quotient of 718 / 6 if my answer choices were 80 or 120?
Use fact families - 8 x 6 = 480 and 120 x 6 = 720 so 120 would be the better choice!
Write the factors of 50 (Use the rules of divisibility to assist you)
50 - (1, 2, 5, 10, 25, 50)
What is the LCM of 12 and 15?
60
A number rounded to the nearest 100 is 1,700. Find the least possible number.
l l l
1,650 1,700 1,749What is the GCF of 3 and 16?
48
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48
16, 32, 48