Math Rules
Rule!
Rule!
If a number ends in either a 5 or a 0, it is divisible by which rule number?
5
If the number 28 is divisible by 4, then what about 728? How do you know?
It is! Because the last 2 digits (28) are divisible by 4
Explain how to check if a number is divisible by 9
Add the sum of the digits together, and if that number is divisible by 9, then so is the whole number
Is the number 640 divisible by 4? How do you know?
Yes, because the last 2 digits (40) are divisible by 4
By finding the sum of the digits, you can tell if a number is divisible by either of these 2 rule numbers
3 and 9
If the number 32 is divisible by 4, then what about the number 330? How do you know?
No it is not. 32 is divisible by 4, but 30 is not, so neither is 330
75 loaves of bread were given to 5 ducks. Could they share equally?
Yes! 75 is divisible by 5
632 cookies are left for 9 people. After dividing them equally, how many are left over?
2 cookies
This rule involves combining the rules for 2 and 3
6
Is 630 divisible by 6? How do you know?
Because it is divisible by both 2 and 3
The number 369 is divisible by these two rule numbers
3 and 9
By subtracting the closest multiple of this number from the first 2 digits you can see if it is divisible by this number
What is 8
If the last 2 digits are divisible by this rule number, so is the whole number
4
Is the number 25160 is divisible by 8
yes because 160 is divisible by 8
The number 45 can be divided by these three rule numbers
3, 5, and 9
246 cookies are left for 4 people. After dividing them evenly, how many are left over?
2
If the last 3 digits are divisible by this rule number, so is the whole number
8
If the number 104 is divisible by 8, then what about 45368
It is ! Because the last 3 digits (368), are divisible by 8
If there are 213 loaves of bread on one side of the road, would 3 ducks cross the road to have equal shares?
Yes! 213 is divisible by 3. But who's to say if the ducks would cross the road
What is a number under 100 that is divisible by 2,3,4,6,8, and 9
What is 72