Blast from the Past
What is the definition of a factor?
Two numbers that are multiplied together to get another number (3 x 4 = 12)
List all the factors of 12
1, 2, 3, 4, 6, 12
List the first 5 multiples of 4
4, 8, 12, 16, 20
Maya has 12 colored pencils. Liliana has 3 times as many. How many colored pencils does Liliana have?
Liliana has 36 colored pencils.
12 x 3 = 36
What is the definition of a multiple?
Skip counting by a number will give you multiples of that number because you are multiplying the original number by 1, 2, 3, etc.
(5, 10, 15, 20 are all multiples are 5)
List all the factors of 20
1, 2, 4, 5, 10, 20
List the first 5 multiples of 7
7, 14, 21, 28, 35
Monty read 30 minutes last night. Spencer read for an hour. How many times as long did Spencer read compared to Monty?
Spencer read for twice as long as Monty.
30 x 2 = 60, or 60 divided by 30 is 2
Is 31 prime or composite? How do you know?
Prime. It only has two factors: 1 and itself.
True or False? If two numbers are related (15 and 60), all the factors of the lower number will always be factors of the higher number.
True! This is because 60 is a multiple of 15, so the factors of 15 will always be factors of 60 as well.
True or False? 55 is a multiple of 11.
True! 11 x 5 = 55
Which TWO numbers are both factors of 20 and 40?
a.) 2
b.) 5
c.) 8
d.) 40
a. (2) and c. (5)
Is 65 prime or composite? How do you know?
Composite. It has more than 2 factors.
Use an array to show to show why all the factors of 10 are also all factors of 40.
Answers will vary, but should show 4 groups of 10 in an array (4x10, 8x5)
The 6th multiple of 9 is what?
54, because 9 x 6 = 54
Which number is NOT a multiple of 9?
a.) 18
b.) 9
c.) 37
d.) 45
c.) 37
Name a composite number that has 2, 3, 5, and 6 as some of its factors.
Answers will vary, but possible answers include 30 and 60
There are 45 girls and 63 boys at Croft. If Ms. Annie wants to create the largest number of classes with equal numbers of boys and girls in each class, a.) how many classes can she create, and b.) how many boys and how many girls will be in each class?
a.) Ms. Annie can create 9 equal classes.
b.) There will be 5 girls and 7 boys in each class.
Ms. Veloz goes to the gym every 4 days, and Ms. Cote goes every 5 days. If they both went to the gym today, when will be the next time they see each other at the gym?
They will see each other in 20 days.
Ms. Veloz goes on day 4, 8, 12, 16, and 20.
Ms. Cote goes on day 5, 10, 15, and 20.
Which number times 25 equals 300?
a.) 4
b.) 6
c.) 10
d.) 12
d.) 12
12 x 25 = 300
(4 x 25 = 100 and 100 x 3 = 300)