Question

Lilly told Abby that 87 was a composite number.
Was she right?
please explain why
Help!

Answer 1

This link will help
http://www.mathsisfun.com/definitions/composite-number.html

Answer 2

And A composite number is a positive integer that has at least one positive divisor other than one or the number itself. So 87 is a composite number.

Answer 3

There are some cool tricks for checking divisibility :)

If the number is even, then it's divisible by 2.

If the sum of the digits add up to a multiple of 3, then it's divisible by 3.
Example: 72. 7+2 = 9, which is a multiple of 3.
So 72 is a composite of 3 and some other factor.

For 4, you look at the last two digits I think...

Some other cool tricks too :d