DIVISIBILITY RULES
• What are
• Quick ways to see if a
divisibility
rules?
number can be evenly
divided by another
number.
• When could
we use
divisibility
rules?
• When finding factors of a
number and reducing
fractions.
• What is the
divisibility
rule for 2?
• Are the
following
divisible by
2:
58390?
• 267?
• 92?
• A number is divisible by 2
if its even, meaning it
ends in 0, 2, 4, 6, or 8.
• Yes (ends in 0, so even)
• No (ends in 7, so odd)
• Yes (ends in 2, so even)
• What is the
• A number is divisible by 3
divisibility
rule for 3?
if the sum of its digits is
divisible by 3.
• Example: 132 is divisible
by 3 because 1+3+2=6
and 6 is divisible by 3.
• 1+3+8=12 and 12 is
divisible by 3, so 138 is
also divisible by 3.
• Is 138
divisible by
3?
• Is 97
divisible by
3?
• Is 402
divisible by
3?
• 9+7=16 and 16 is not
divisible by 3, so 97 is
not divisible by 3 either.
• 4+0+2 = 6 and 6 is
divisible by 3, so 402 is
also divisible by 3.
Multiples of 5
• What is the
divisibility
rule for 5?
• Are the
following
divisible by
5: 108?
• 85?
• 310?
• A number is divisible by 5
if it ends in a 0 or 5.
• No, it ends in 8.
• Yes, it ends in 5.
• Yes, it ends in 0.
What are the multiples of 10? What do they
have in common?
• What is the
divisibility
rule for 10?
• Are the
following
divisible by
10: 105?
• 80?
• 230?
• A number is divisible by
10 if it ends in a 0.
• No, it ends in 5.
• Yes, it ends in 0.
• Yes, it ends in 0.
• Of 2, 3, 5,
• 2 yes (ends in 0 so even)
and 10,
which are
factors of
230?
• 3 no (2+3+0 = 5, which is
not divisible by 3)
• 5: yes (ends in 0)
• 10: yes (ends in 0)
• Of 2, 3, 5,
and 10,
which are
factors of
105?
• 2 no(ends in 5 so odd)
• 3 yes(1+0+5 = 6, which is
divisible by 3)
• 5: yes (ends in 5)
• 10:no (does not end in 0)
• Fully reduce
180
220
Direct Station
• We will learn a few more divisibility rules: how to quickly
tell when a number has a factor of 4, 6, or 9.
• We will write down the work for this station in our
notebook instead of on our work paper.
Collaborative Station
• Spin the number spinner 3 times. Use the numbers you
land on to create a 3 digit number.
• Example: If you spin a 4, a 0, and a 5, your number is
405. If you spin a 0, 8, and 2 your number is 82.
• You and your partner will determine whether your number
is divisible by 2, 3, 5, and 10.
Collaborative Station Example
• Say you and your partner spin the number 135.
• Write:
• 135:
not divisible by 2 because it ends in 5, not an even
divisible by 3 because 1+3+5=9, which is divisible by 3.
divisible by 5 because it ends in 5.
not divisible by 10 because it does not end in 0
Independent Station: ST Math
• If you are still on the diagnostic test, finish that.
• Otherwise, continue the properties of operations unit.
• Write down the order of operations problems on your work
paper as you do them on the computer.