What Are Integer Rules?
Question
A positive, divided by a negative, equals
00:00
00:00
Hi, my name is Bassem Saad. I'm an associate math instructor and a Ph.D. candidate, and I'm here today for About.com to introduce integer rules. Integers are counting numbers that can take either positive or negative signs, and the integer rules tells us how we can add, subtract, multiply or divide these numbers. So let's begin.

The first set of integer rules are for addition and subtraction. Whenever we have two numbers with the same signs, we will add the numbers and carry the sign straight across to the answer. So when the signs are different, subtract the numbers and carry over the sign of the number with the largest absolute value. So four, minus seven, equals minus three, because four is less than seven; and minus five, plus nine, equals positive four, because five is less than nine.
More Interger Rules

So here are the rules for integer multiplication. A negative number, times a negative number, equals a positive number; so negative eight, times negative five, equals positive 40. A negative, times a positive, equals a negative; so negative eight, times five, equals negative 40. A positive, times a negative, equals a negative; so positive eight, times negative five, equals negative 40.
Integer Rules

Finally, a positive, times a positive, equals positive; eight, times five, equals 40. So the rules are the same for division. A negative, divided by a negative, equals a positive; negative eight, divided by negative two, equals four. A negative, divided by a positive, is a negative; so negative eight, divided by two, equals negative four. A positive, divided by a negative, equals a negative; so eight, divided by negative two, equals negative four. And a positive, divided by a positive, equals a positive; so eight, divided by two, equals a four. So now we know what integer rules are.