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Name: ____________________________
Divisibility – a number is divisible by another number if the quotient is a whole number.
A number is divisible by...
Divisibility Rules
2
If the number ends in a 0, 2, 4, 6, 8
3
Add the digits of the number. If the sum is divisible by 3 then
the original number is divisible by 3.
4
If the last two digits are divisible by 4 (or end in 00)
5
If the number ends in 0 or 5
6
Even numbers only. Must be divisible by both 2 and 3.
7
check
8
Must be even, divisible by 2 and 4 and you still have to check it.
9
Add the digits of the number. If the sum is divisible by 9 then
the original number is divisible by nine.
10
If the number ends in 0
Use the divisibility rules to tell whether each number is divisible by 2, 3, 4, 5, 6, 7, 8, 9
and 10.
1) 120 ___________________________
2) 435 ___________________________
3) 228 ___________________________
4) 540 ___________________________
5) 144 ___________________________
6) 634 ___________________________
Prime Numbers – are numbers that are only divisible by one and itself.
Composite Numbers – are divisible by more than two numbers.
Tell whether each number is prime or composite. (hint: use the divisibility rules!)
7) 12 _____________
8) 17 _____________
9) 28 _____________
10) 9 _____________
11) 37 _____________
12) 79 _____________
13) 72 _____________
14) 55 _____________
16) 67 _____________
Factors – are whole numbers that divide the product with no remainder.
Find all the factors of the following numbers.
1) 20 ___________________________
2) 35 ___________________________
3) 31 ___________________________
4) 50 ___________________________
Greatest Common Factor (GCF) – is the largest number that is a factor for any set of
two or more numbers.
Find the GFC for each set of numbers.
5) 32 and 48
6) 45 and 81
7) 18 and 36
32 = _________________
48 = _________________
45 = _________________
81 = _________________
18 = _________________
36 = _________________
GFC = _______
GFC = _______
GFC = _______
8) 14 and 35
9) 42 and 72
10) 56 and 64
14 = _________________
35 = _________________
42 = _________________
72 = _________________
56 = _________________
64 = _________________
GFC = _______
GFC = _______
GFC = _______
11) 28, 56 and 84
12) 30, 45, and 75
13) 36, 45, and 54
28 = _________________
56 = _________________
84 = _________________
30 = _________________
45 = _________________
75 = _________________
36 = _________________
45 = _________________
54 = _________________
GFC = _______
GFC = _______
GFC = _______