SOLUTIONS
NUM BER SENSE & NUM ERATI ON: FACT ORS & MULT I PL ES
Don’t forget to play the Grid Game first! Go to mathfrog.ca for the link.
A factor of a number divides into it without a remainder.
1. List all the factors of the following numbers.
a) 8 1, 2, 4, 8
b) 15 1, 3, 5, 15
c) 24 1, 2, 3, 4, 6, 8, 12, 24
d) 25 1, 5, 25
e) 36 1, 2, 3, 4, 6, 9, 12, 18, 36
f) 63
1, 3, 7, 9, 21, 63
2. For each pair of numbers, list the individual factors. Then determine the greatest common factor (GCF).
a) 16 1, 2, 4, 8, 16
32 1, 2, 4, 8, 16, 32
GCF 16
b) 12 1, 2, 3, 4, 6, 12
30 1, 2, 3, 5, 6, 10, 15, 30
GCF 6
c) 27 1, 3, 9, 27
54 1, 2, 3, 6, 9, 18, 27, 54
GCF 27
3. Determine the greatest common factor (GCF) of each of the following pairs of numbers.
a) 7 and 9 1
b) 14 and 49 7
c) 20 and 60
20
d) 48 and 56 8
The multiples of a number are those numbers which it will divide into exactly.
4. List the first three multiples of each number.
a) 5
5, 10, 15
b) 3 3, 6, 9
c) 7
7, 14, 21
d) 12 12, 24, 36
5. Circle all the numbers that are not multiples of 6.
30
44
39
18
1
72
12
64
56
94
60
6. a) List the multiples of 6 and 8 which are less than 100.
6
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90, 96
8
8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96
b) Which multiples do 6 and 8 have in common? 24, 48, 72, 96
Expectation: identify and describe the characteristics of multiples and factors, composite and primes to 100
21
c) What is their least common multiple (LCM)? 24
7. Write the least common multiple of each pair of numbers.
FUN MATH FACT
a) 5 and 10 10
b) 3 and 4
12
c) 7 and 9
63
The number
2 is the only
prime number
that is even!
d) 4 and 6 12
8.
Koku and Dennis were discussing prime and composite numbers. Koku said that 21 was a prime number,
but Dennis said that it was a composite number. Who was correct? Explain.
21 is not a prime number, so Dennis is correct. A prime number has exactly 2 factors, but 21 has more
than 2 factors: 1, 3, 7, 21.
9.
Multiples of 12 are also multiples of another number. Circle the number.
a) 4
b) 5
c) 7
d) 8
e) 10
TRY THIS!
a) Colour those squares black that are factors of 100.
b) Colour those squares green that are multiples of 7.
c) Colour those squares yellow that are multiples of 9 or multiples of 11.
d) Colour those squares red that are multiples of 12 or factors of 60.
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What do you see? A flower
Expectation: identify and describe the characteristics of multiples and factors, composite and primes to 100
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