Digits, Grade 7, Volume 1, Homework Helper

### 1-3: Subtracting Rational Numbers

#### Key Concept

You subtract a fraction or a decimal the same way you subtract an integer.

For any rational numbers a and b:

ab = a + (− b)

a − (− b) = a + b

table with 4 rows and 3 columns , row1 column 1 , cap writesubtractionasaddingtheopposite. , column 2 minus , 3 fifths , minus , 4 fifths , column 3 equals negative , 3 fifths , plus . open , negative , 4 fifths , close , row2 column 1 , cap addnumberswiththesamesign. , column 2 , column 3 equals negative , 7 fifths , row3 column 1 , cap writesubtractionasaddingtheopposite. , column 2 negative 9.1 minus . open , negative 7.6 , close , column 3 equals negative 9.1 plus 7.6 , row4 column 1 , cap addnumberswithdifferentsigns. , column 2 , column 3 equals negative 1.5 , end table

#### Part 1

Example Predicting The Sign of Differences of Rational Numbers

Determine if each difference is negative, zero, or positive.

• a. 1 half , minus . open , negative , 1 fourth , close

• b. negative 5 minus . open . negative 3 , and 3 fourths . close

• c. negative 4.7 minus . open , negative 4.7 , close

• d. 5.7 minus 8 , and 1 half

• e. − 2.6 − (− 3.1)

• f. negative 3 , and 1 half , minus . open . negative 3 , and 1 half . close

• g. negative , 4 thirds , minus . open , negative , 2 thirds , close

• h. negative 0.8 minus 0.8

Solution