Chapter 1 · Numbers · page 3 of 68
Multiplying and dividing signs
levelPre-algebra
standard7.NS.A.2
practiceInteger operations
For multiplying and dividing, count the negative signs. An even count gives a positive result. An odd count gives a negative one. The sizes multiply or divide as usual.
How to use it
- Multiply or divide the sizes, ignoring signs.
- Count the negatives. Even means positive, odd means negative.
Example
Where it goes wrong
- Using the addition rule here. Two negatives added stay negative; two negatives multiplied become positive.
- Forgetting that a lone negative in a product makes the whole product negative.