Rational Numbers and Decimals
Adding Rational Numbers
Subtracting Rational Numbers
Multiplying Rational Numbers
Dividing Rational Numbers
100
Turn -9/25 into a decimal
-0.36
100
2.75+(-2)+(-5.25)
-4.5
100
(-2/9)-(-3)
2 and 7/9
100
(-3/4)x(-4)
3
100
-120/-6
20
200
Write 7 and 3/5 as a decimal.
7.2
200
(1/4)+(-3/4)
-1/2
200
(-0.5)--3.5
-4
200
(-2/3)x(1/2)x(-6/7)
2/7
200
-10.35/-2.3
4.5
300
What is a rational number?
A decimal that repeats or terminates. Rational numbers can be written as fractions.
300
A contestant on a game show has 30 points. She answers a question correctly to get 15 points. Then she answers a question incorrectly and loses 25 points. What is the contestant's final score?
30+15+9-25)=20 points
300
At the beginning of a lab experiment, the temperature of a substance is -12.6 degrees Celsius. During the experiment, the temperature of the substance decreases 7.5 degrees. What is the final temperature of the substance?
(-12.6)-7.5=-20.1 degrees Celsius
300
The ground temperature at Brigham Airport is 12 degrees Celsius. The temperature decreases by 6.8 degrees for every increase of 1 km above the ground. What is the overall change in temperature outside a plane flying at an altitude of 5 km above Brigham Airport?
5(-6.8)=-34 degrees
300
A hot air balloon descended 99.6 meters in 12 seconds. What was the balloon's average rate of descent in meters per second?
8.3 meters per second
400
Describe two ways you could evaluate 37% of the sum of 27 and 15.9
(1) Find the sum of the two numbers and multiply the result by 0.37 or (2) multiply each number by 0.37 and then add the products
400
What is an additive inverse?
A number that is the same distance from zero on the number line as another number, just on the other side of the number line.
400
Evan said that the difference between two negative numbers must be negative. Was he right?
No, sometimes the answer is positive. -5-(-8)=3
400
Find two integers whose sum is -13 and whose product is 30.
-10 and -3
400
Divide 5 by 4. Is your answer a rational number? why or why not?
Yes. It is rational because 5/4=1.25 which terminates and is therefore rational
500
Three rock climbers started a climb with each person carrying 7.8 kg of climbing equipment. A fourth climber with no equipment joined the group. The group divided the total weight of climbing equipment equally among the four climbers. How much did each climber carry?
5.85 kg
500
Can you find the sum [5.5+(-2.3)]+(-5.5+2.3) without performing any additions? Explain.
Yes, 5.5 and -5.5 are opposites and 2.3 and -2.3 are opposites so the sum will be zero since the sum of opposites is zero.
500
Must the difference between two rational numbers be a rational number?
Yes. Since both numbers are rational, each can be written as a fraction. A fraction minus a fraction is a fraction which is rational.
500
For home economics class, Sandra has 5 cups of flour. She made 3 batches of cookies that each used 1.5 cups of flour. Write and solve an expression to find the amount of flour Sandra has left after making the 3 batches of cookies.
5-3(1.5)=0.5 cup
500
Should the quotient of an integer divided by a nonzero integer always be a rational number? Why or why not?
Yes. Since an integer divided by another integer is a ratio of two integers and the denominator is not zero, the number is always rational.
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