Transcript divisibility rules for 3 and 9

YESTERDAY ….
You learned the rules for divisibility
A number that can be equally shared in whole parts is divisible by
2 if the number is even ( ends in 0,2,4,6,8,)
Is divisible by 5 is it ends in 5 or 0
Is divisible by 10 is it ends in 0
Today we will learn the rules for divisibility by 3 and 9.
THERE ARE SIMILARITIES IN RULES FOR 3 & 9
To find out if
something is
divisible by 3 , add
the digits.
117
Add 1 +1+ 7=9
9 is divisible by 3,
therefore 117 is
divisible by 3.
To find out is
something is
divisible by 9, add
the digits.
8217
Add 8+2+1+7=18
18 is divisible by 9,
therefore 8217 is
divisible by 9.
3 and 9 use the digit
sum rule . Now it’s
time for an
annoying rap about
it !
http://www.youtube.c
om/watch?v=1ffvCt
NZN9Q
READY FOR PRACTICE ?
Put your answers in your coil note book.
Which numbers are divisible by 3 ? Which by 9 ?
a) 117
b) 216
c) 4125
d)729
e) 8217
f)12 024
READY FOR MORE PRACTICE ?
http://www.funtrivia.com/playquiz/quiz2534921d05d68.html
http://www.oswego.org/ocsd-web/match/dragflip.asp?filename=slanedivrules
Turn to page 12 in the grade 7 MMS brown text book to see and study the divisibility
rules.