Pre Divisor

In previous section we learned that 12 is a multiple of 4, because 12 equals 4 times an integer. We can also express this fact by saying, “4 is a (a)   of 12.”

Let a be a nonzero integer and b be an integer. We say that a is a (a)   of b if is a multiple of a

The nouns “divisor” and “factor” mean the (a)   thing. For example, the positive factors of are 1, 2, 3, and 6.

One way we sometimes think of divisors is as “ a is a divisor of b if dividing b by a leaves (a)   .”

because 60 divided by 6 has no remainder, 6 is a divisor of 60.

• True

• False

Since 72 divided 5 by has remainder 2, we know that 5 is not a divisor of 72.

• True

• False

Note that 20 is a divisor of 60.. Must every divisor of 20 also be a divisor of 60?

• Yes

• No

Note that 20 is a divisor of 60. Must every divisor of 60 also be a divisor of 20?

• Yes

• No

If a is a divisor of b, then every divisor of a is also a divisor of b .

• True

• False

• Yes

• No