 page 1, How to Add, Subtract, Multiply, Divide Signed Numbers  Writtten
How to Add Signed Numbers  

How to Subtract Signed Numbers  
SUBTRACTION means ADD THE OPPOSITE.

How to Multiply or Divide Signed Numbers  
As with the other operations above, the rules are stated, examples and a quiz provided. But, this time take a brief detour for an explanation.
But Why? It is convenient to think of multiplication and division of signed numbers in terms of factors and opposites  more specifically in the kind of computation shown on the Opposites on Your Computer's Calculator page. The expression (2)(4)(3) also means(1)(2)(1)(4)(3). This may be rearranged as (1)(1)(2)(4)(3). But, that's also ((12)), the opposite of the opposite of twelve. So, when multiplying or dividing signed numbers, use the number of negative signs to determine the sign of the answer because each opposite of an oppisite is the original number.

All Together, Now  
Now that you've mastered the basics of signed number computation, you are ready to see more than one operation in an expression. Please continue to Lesson 80 on Order of Operations. 
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