Review of Introductory Mathematics
SIGNED NUMBERS
Multiplication
Multiplication of signed numbers may be performed by using the following rules:
The product of any two numbers with like signs is positive:
(+)(+) = (+) or (–)(–) = (+).
The product of any two numbers with unlike signs is negative:
(+)(–) = (–) or (–)(+) = (–).
The product is negative if there is an odd number of negatives.
The product is positive if there is an even number of negatives.
Example:
(+3)(+3) = +9
(–2) (+4) = –8
(–1) (–2) (+1) (–2) = –4
(–2) (+2) (+2) (–2) = +16
Zero times any number equals zero.
Multiplying by –1 is the equivalent of changing the sign.
Division
Division of signed numbers may be performed using the following rules:
Rule 1:
The quotient of any two numbers with like signs is positive:
(+)/(+) = (+) or (–)/(–) = (+)
Rule 2:
The quotient of any two numbers with unlike signs is negative:
(+)/(–) = (–) or (–)/(+) = (–)
Rule 3:
Zero divided by any number not equal to zero is zero.
Rev. 0
Page 51
MA-01
