Download Altamont Pre-test - Weatherly Math Maniacs

Prime Numbers, Factors & Multiples
Practice
1. What is the smallest prime number?
2. How many prime numbers have value less than 100?
3. What is the largest prime number less than 500?
4. Find the largest prime number less than 100.
5. What is the sum of all primes less than 50?
6. The product of 3 different primes is always divisible by exactly __ different
non-prime numbers greater than 1.
7. Write 12 as a product of prime numbers.
8. Write 20 as a product of prime numbers.
9. List all the primes that 12 and 20 share.
listed in #8.
Now multiply the numbers you just
The result is called the greatest common factor, or GCF, of 12 and 20.
10.
Find the GCF of 28 and 36.
Page 1 of 3
What is a factor?
1. List all pairs of factors of 12.
1 & ___, 2 & ___ . 3 & ___
2. List all pairs of factors of 20. ___& ___, ___ & ___, ___ & ___
3. Will there always three pairs of factors?
4. Are the factors always prime numbers?
More Practice
5. 50 x 50 = 25 x 25 x _____
6.
and 80 x 80 x 80 = 20 x 20 x 20 x _____
27 ÷ 3 = 3 x ___
7. Two million equals which of the following:
a) 200 x 100
c) 2000 x 1000
b) 200 x 1000
d) 20000 x 10
8. 3 x 6 x 18 = 27 x ____
9. (32 x 4) + (32 x 5) + (32 x 6)
Find a short way!
10. How many positive two-digit numbers less than 40 have an odd number of
divisors?
11. What is the sum of the numbers less than 35 that have exactly 8 factors?
12. How many positive integer divisors does 144 have?
13. The greatest common divisor of 60, 160, and 260 is
a) 5
c) 20
b) 6
d) 60
14, Every _____ number has at least one even prime factor.
15. If I multiply two integers and their product is 36, their sum CANNOT be
a) 16
c) 13
b) 15
d) 12
Page 2 of 3
Multiples
Multiples of 2 are called _____ numbers.
Integers that are NOT divisible by 2 are called _____ numbers.
What do you get if you multiply two even numbers?
What is the product of an even and an odd?
If you multiply an odd and an odd, you get a(n) ______ number.
Now, think of the same questions for the sum of two numbers:
even + even = _______
even + odd = _______
odd + odd = _______
1. The product of 2009 and any even number is always_______.
2. How many three-digit even numbers are greater than 827?
3. (33 + 44 + 55 + 66) ÷ 11 =
4. What is the largest multiple of 6 less than 1000?
5. What is the least common multiple of 6 and 9?
6. What is the LCM of 12 and 15?
7. Find the LCM of 10 and 16.
8. The smallest whole number divisible by both 24 and 36 is _____.
9. In the division (121,121,121,003) ÷ 11, what is the remainder? ____
a) 2
c) 4
b) 3
d) 5
e) 6
10. How many two-digit whole numbers are multiples of both 8 and 12?
11. What is the product of the least common multiple and the greatest common
factor of 21 and 34?
Page 3 of 3