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7.8 multiplying real numbers
1. Multiplying Signed Numbers
GUIDED EXAMPLE 1 Multiply.
SOLUTION
STEP RESULT
Multiply the numerical parts.
Determine the sign of the product.
Answer
The two factors have different
signs, so the sign of the
product is negative.
2. Multiplying Signed Numbers
GUIDED EXAMPLE 2 Multiply.
SOLUTION
STEP RESULT
Multiply the numerical parts.
Determine the sign of the product.
Answer
The two factors have different
signs, so the sign of the
product is negative.
3. Multiplying Signed Numbers
GUIDED EXAMPLE 3 Multiply.
SOLUTION
STEP RESULT
Convert the mixed number into an improper fraction.
Multiply the numerical parts.
Determine the sign of the product. The two factors have different
Answer
signs, so the sign of the product
is negative.
Convert the improper fraction into a mixed number.
4. Multiplying Signed Numbers
GUIDED EXAMPLE 4 Multiply.
SOLUTION
STEP RESULT
Multiply the numerical parts.
Determine the sign of the product.
Answer
The two factors have different
signs, so the sign of the
product is negative.
5. Multiplying Signed Numbers
GUIDED EXAMPLE 5 Multiply.
SOLUTION
STEP
Multiply the numerical parts.
RESULT
Determine the sign of the product.
Answer
The two factors have the same
sign, so the sign of the product
is positive.
6. Multiplying Signed Numbers
GUIDED EXAMPLE 6 Multiply.
SOLUTION
STEP
Multiply the numerical parts.
RESULT
Determine the sign of the product.
Answer
The two factors have the same
sign, so the sign of the product
is positive.
7. Multiplying Signed Numbers
GUIDED EXAMPLE 7 Multiply.
SOLUTION
STEP
RESULT
Multiply the numerical parts.
Determine the sign of the product. The two factors have the same
Answer
sign, so the sign of the product
is positive.
8. Multiplying Signed Numbers
GUIDED EXAMPLE 8 Multiply.
SOLUTION
STEP PROCESS
Multiply the numerical parts of the
first two numbers.
RESULT
Multiply the product by the numerical
part of the next number.
Multiply that product by the
numerical part of the next
number.
Determine the sign of the product. There is an
even number of
negative factors.
Answer
Positive product
9. Multiplying Signed Numbers
GUIDED EXAMPLE 9 Multiply.
a.
NUMBER OF NEGATIVE
FACTORS
EXAMPLE PRODUCT
b.
c.
d.
10. Multiplying Signed Numbers
GUIDED EXAMPLE 10 Multiply.
a.
NUMBER OF NEGATIVE
FACTORS
EXAMPLE PRODUCT
b.
c.
d.
11. Study Guide
Procedure: MULTIPLYING TWO NUMBERS WITH DIFFERENT SIGNS
To multiply two numbers with different signs:
1. Multiply the absolute values, or the numerical parts.
2. Your answer will always be negative.
Procedure: MULTIPLYING TWO NUMBERS WITH THE SAME SIGN
To multiply two numbers with the same sign:
1. Multiply the absolute values, or the numerical parts of the numbers.
2. Your answer will always be positive.
Notes:
When multiplying an even number of negative factors, the product
is positive.
When multiplying an odd number of negative factors, the product
is negative.
