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Square Numbers and Square Roots
Divisibility Rules
Factors
Factor Strings
Prime and Composite Numbers
100
What is the square root of 4?
2
100
Is 58 divisible by two? Why or why not?
Yes. It ends in an even number.
100
What are the factors for 15?
1, 3, 5, 15
100
Give me a factor string for 18.
2*3*3
100
Is 3 a prime or composite number? Why?
Yes. Only has the factors of 1 and itself.
200
What is the square root of 16?
4
200
Is 45 divisible by 3? Why or why not?
Yes. 15 divisible because the sum of its digits is divisible by 3.
200
What are the factors for 32?
1, 2, 4, 8, 16, 32
200
What is the length of this factor string: 3*5*2*2=60
4
200
Is 12 a prime or composite number? Why?
Composite because it has more than two factors. 1, 2, 3, 4, 6, 12
300
What is 7^2?
49
300
Is 39 divisible by 3? Why or why not?
Yes 13. This is because the sum of its digits are divisible by 3.
300
What are the factors for 100?
1, 2, 4, 5, 10, 20, 25, 50, 100
300
Give me a factor string for 25.
5*5
300
Is 16 a prime or composite number? Why?
Composite because it has more than two factors.
400
What is 9 squared?
81
400
Is 125 divisible by 5? Why or why not?
Yes 25. This is because the number ends in a 5 (or a zero).
400
What are the factors for 54?
1, 2, 3, 6, 9, 18, 27, 54
400
Can this be a factor string: 1*7? Why or why not?
No. One cannot be used as a factor in a factor string.
400
Is 17 a prime or composite number? Why?
Prime because it only has the factors 1 and 17.
500
What is the square root of 25?
5
500
Is 105 divisible by 10? Why or why not?
No. This is because it does not end in a zero.
500
What are the factors for 150?
1, 2, 3, 5, 6, 10, 15, 25, 30, 50, 75, 150
500
Give me a factor string and the length of the factor string for 42.
2*3*7 Length: 3
500
Is 20 prime or composite? Why?
Composite because it has more than two factors. 1, 2, 4, 5, 10, 20