Arithmetic Grade Five
Lesson Sixty-two: Divisibility
Which of the following are divisible by 3?
12, 33, 20, 21, 26, 16, 15, 22.
Can you easily tell which numbers in this list are divisible by three and
which aren't. If you have to you can write out a list of count-bys for 3 or
divide each number on the list by 3 to see if there is a remainder or not.
In this list, 12, 33, 21, and 15 ARE DIVISIBLE BY 3. The numbers which are
not divisible by 3 in this list are 20, 26, 16, and 22.
Which of the following are divisible by 6?
21, 30, 25, 24, 18, 19, 35, 36, 40, 42.
You should be able to easily sort out the numbers which are divisible by 6
from the ones that aren't. In this list 30, 24, 18, 36, and 42 ARE DIVISIBLE
BY 6. The numbers which are not divisible by 6 in this list are 21, 25, 19,
35, and 40.
Here are some numbers sorted by whether or not they are divisible by 7.
| 21 | YES |
| NO | 16 | |
| 35 | YES |
| 42 | YES |
| NO | 30 | |
| 49 | YES |
Now you will try a few of these yourself.
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