General Rules
(+) x (+) =
(+) or positive
-4.4 x (-6.02)
26.488
-4.95 ÷ 1.5
-3.3
3 9/10*(-2 2/3)
-10 2/5
-1 5/6-:4 1/6
-11/25
Describe and correct the error.
2/3*(-3/4)=1/2
The answer should be negative because a positive times a negative is a negative.
(+) x (-) =
-
-9.4 x (-4.7)
44.18
6.4 ÷ (-3.2)
-2
5/8*(-4/15)
-1/6
-4/11-:2/7
-1 3/11
Describe and correct the error.
-3/8-:-4/5=-15/32
The answer should be positive because a negative divided by a negative is a positive.
Tell whether the expression is positive or negative without evaluating.
-3/10 * (-8/15)
positive
-7.2 x 0.1 x (-100)
72
-15.4 ÷ (-2.5)
6.16
-2 3/8*(-1 3/5)
3 4/5
9/10-:(-1 1/5)
-3/4
0.9*(-1.3)=-11.7
The answer should be -1.17. The decimal is in the wrong place since there are two decimal places in the problem, there should be 2 decimal places in the answer.
How is multiplying and dividing rational numbers similar to multiplying and dividing integers?
The same rules for signs of integers are applied to rational numbers.
A 14.5-gallon gasoline tank is
3/4
full. How many gallons of gasoline are already in the tank?
10 7/8 gallons
32.436 ÷ (-4.24)
-7.65
The elevation of a sunken ship is -120 feet. Your elevation is
5/8
of the ship's elevation. What is your elevation?
-75 ft
-4 1/6-:1 1/3
-3 1/8
Describe and correct the error.
-34.84-:(-5.2)=-67
The answer should be 6.7. A negative divided by a negative is a positive, and the decimal is in the wrong place.
Tell whether the expression is positive or negative without evaluating.
-6/5-:(-1/2)*6.3*(-0.6)-:2/3*7 7/8-:100
negative
-6 x (-0.05) x (-0.4)
-0.12
How many 2.25-pound containers can you make with 24.75 pounds of almonds?
11 containers
-3/5*2 2/7(-3 3/4)
5 1/7
How many
1 1/4
pound packages can you make with
7 1/2
pounds of cashews?
6 packages
Describe and correct the error.
-1/4-:3/2=-4/1*3/2=12/2=-6
The wrong fraction was inverted (reciprocal).
-1/4-:3/2=-1/4*2/3=-1/6