Digits, Grade 7, Volume 1, Homework Helper

### 1-4: Multiplying Rational Numbers

#### Key Concept

The sign rules for multiplying integers work for all rational numbers. #### Part 1

Example Predicting Signs for Products of Rational Numbers

Is each product positive or negative? Explain.

• a. − 13 × (− 3) × (− 3)

• b. negative , 1 half , middle dot 12 middle dot . open , negative , 1 fourth , close

• c. − 0.06 × (− 1.3)

• d. 2 thirds , open negative 7 close

• e. 5.1 · (− 4.7)

• f. negative 3 , and 1 half , times 5 , and 6 sevenths

• g. − 0.5.(1.5)(− 0.6)(− 2)

• h. negative , 1 eighth . open , negative , 7 eighths , close . open 10 close

Solution

Sample explanations:

• a. An odd number of negative factors give a negative product.

table with 4 rows and 1 column , row1 column 1 , negative 13 times open negative 3 close times open negative 3 close , row2 column 1 , open negative close open negative close open negative close , row3 column 1 , open plus close open negative close , row4 column 1 , minus , end table

• b. An even number of negative factors give a positive product.

table with 4 rows and 1 column , row1 column 1 , negative , 1 half , middle dot 12 middle dot . open , negative , 1 fourth , close , row2 column 1 , open negative close open plus close open negative close , row3 column 1 , open negative close open negative close , row4 column 1 , plus , end table

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