Zero belongs to the second set but not the first.
http://wiki.answers.com/Q/What_is_the_difference_b...

1. Multiply the factors or divide when you need to multiply and divide positive integers. When you have done that, it is time to look at the signs. In the example below, it would
http://www.ehow.com/how_4448901_multiplydividepo...

Positive integers are 1, 2, 3, 4,
http://www.chacha.com/question/whatarepositivea...

Overview Positive and negative integers are the integers other than zero. Integers the "natural numbers" in mathematics, for example 3, 2, 1, 1, 2, 3. The number zero
http://www.soyouwanna.com/positivenegativeintege...
