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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Table of Contents

Digits, Grade 7, Volume 1, Homework Helper Unit A: Number and Operations Unit B: Expressions, Equations, and Relationships Unit C: Measurement and Geometry Unit D: Proportionality English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties