## Wednesday, December 14, 2011

### Textbook Question #4 on page 222

Question:
Copy and complete the table. If the number in the left column is divisible by the number in the top row, put a . If it is not divisible, put an X.

Solution:
Lets start with 630. 630 is divisible by 2, 5 and 10 because 630 ends in 0. It's divisible by 3 and 9 because the sum of the number is 9. 9 is divisible by 3 and 9. It's divisible by 6 because it's divisible by both 2 and 3.

The next number is 5184.  It is divisible by 2 because it ends in 4, an even number. It is divisible by 3 and 9 because the sum of the number is 18. 18 is divisible by both 9 and 3. It is divisible by 4 because if you divide 5184 by 2 twice, you get a number with no remainder. It's divisible by 8 because if you divide 5184 by 2 thrice, you get a number with no remainder.

This number, 2035 is only divisible by 5 because 2035 ends in 5.

Finally, 810 is divisible by 2, 5 and 10 because 810 ends in 0. It's divisible by 9 and 3 because the sum of the number is 9, which can be divided evenly by 9 and 3. It is divisible by 6 because 810 is divisible by both 2 and 3.

I hope this video helps.