multiply%20rational%20numbers.

1
ObjectiveThe student will be able to

• multiply rational numbers.
• SOL none

Designed by Skip Tyler, Varina High School and
Nicole Kessinger Deep Run High School
2
Multiplying Rules

• 1) If the numbers have the same signs then the
  product is positive.
• (-7) (-4) 28
• 2) If the numbers have different signs then the
  product is negative.
• (-7) 4 -28

3
Examples 1) (3x)(-8y)
-24xy
Write both numbers as a fraction. Cross-cancel if
possible.
Multiplying fractions top top Bottom
bottom
4
When multiplying two negative numbers, the
product is negative.

1. True
2. False

5
When multiplying a negative number and a positive
number, use the sign of the larger number.

1. True
2. False

6
(No Transcript)
7
Multiply (-3)(4)(-2)(-3)

1. 72
2. -72
3. 36
4. -36

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an easy way to determine the sign of the answer
When you have an odd number of negatives, the
answer is negative. When you have an even number
of negatives, the answer is positive.
4) (-2)(-8)(3)(-10) Do you have an even or odd
number of negative signs?
3 negative signs -gt Odd -gt answer is negative -480
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Positive or negative answer? Positive - even of
negative signs (4)
Write all numbers as fractions and multiply.
12
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What is the sign of the product of
(-3)(-4)(-5)(0)(-1)(-6)(-91)?

1. Positive
2. Negative
3. Zero
4. Huh?