Module VI Notes
Signed Numbers : A signed number is a number that is preceded by a + or - sign . This sign indicates the direction of the number with respect to zero on the Real Number Line . For example , -5 is five units left of 0 ( the origin ) on the Real Number Line . +5 would be five units to the right of 0 . The absolute value of a signed number is always positive . Thus |-5| = 5 and |5| = 5 .
Before working equations with signed numbers it is important to understand the rules of operations with signed numbers .
Multiplying
any even number of minus signs produces a positive product . (-8)(-5)(-1)(-2) = 80.Multiplying any
odd number of minus signs produces a negative answer . (-6)(-3)(-1) = -18 .Dividing a minus by a minus produces a positive quotient :
A single minus sign in a division problem gives a negative answer :
Example: Simplify completely (-3)(-4)-(-6)(3)-(-4)(1/-2)