ACTIVITY
“What’s Next?
3, 6, 9, 12, ___
15
6, 12, 18, 24, ___
30
12, 24, 36, 48, ___
60
Lesson 2:
Divisibility Rules
for 3, 6 and 9
Objective:
*Use divisibility rules for 3, 6
and 9 to find the common
factors.
Divisibility by 3:
*to determine if a number is
divisible by 3, ADD the digits of
the number. If the sum of the
digits is divisible by 3, then the
number is divisible by 3.
Example:
6 312 divisible by 3
6 + 3 + 1 +2 = 12
12 is divisible by 3,
so 6312 is divisible by 3
Example:
27 531 divisible by 3
2 + 7 + 5 + 3 + 1 = 18
18 is divisible by 3,
so 27 531 is divisible by 3
Divisibility by 6:
*A number must be EVEN, if
we ADD the digits of the
number the sum of the digits is
divisible by 3 then it is must be
divisible by both 3 and 2.
Example:
1242 divisible by 6
1 + 2 + 4 + 2 = 9 (divisible by 3)
1242 = even numbers
(divisible by 2)
so 1242 is divisible by 6
Example:
3636 divisible by 6
3 + 6 + 3 + 6 = 18
(divisible by 3 and 2)
so 3636 is divisible by 6
Example:
234 780 divisible by 6
2 + 3 + 4 + 7 + 8 + 0= 24
24 is divisible by both 3 and 2
so 234 780 is divisible by 6
Divisibility by 9:
*A number is divisible
by 9 if the sum of its
digits is a multiple of 9.
Example:
162 divisible by 9
1 + 6 + 2 = 9 (divisible by 9)
so 162 is divisible by 9
Example:
4 626 divisible by 9
4 + 6 + 2 + 6 = 18
(divisible by 9)
so 4 626 is divisible by 9
Example:
36 054 divisible by 9
3 + 6 + 0 + 5 + 4 = 18
(divisible by 9)
so 36 054 is divisible by 9
PRACTICE
3
1. 498
2. 9, 639
3. 1, 125
4. 20,250
5. 24, 564
6
9
Write a digit on the line to
form the GREATEST
possible number divisible by
the second number.
1. 2 4___
3 ; 9
8 ; 6
2. 4 2 7 __
8 40;
3. 3 __
3
Write a digit on the line to form the
GREATEST possible number divisible by
the second number.
4. 2 4 2 ___
4 ; 6
5. 8 4 2 1 __
3 ;
6. 4 __
9 125;
9
3