Show What You Know® on the Common Core
7.RP.A.2a
Proportional Relationships
4.
Mathematics Flash Cards for Grade 7
Which graph displays direct variation, or a proportional
relationship?
y
y
A.
5
4
3
2
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
-1
-2
-3
-4
-5
x
C.
5
4
3
2
1
-4
-3 -2 -1 0 1 2 3 4 5
-5
-1
-2
-3
-4
-5
y
y
B.
x
5
4
3
2
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
-1
-2
-3
-4
-5
x
D.
5
4
3
2
1
-5 -4 -3 -2 -1 0 1 2 3 4 5
-1
-2
-3
-4
-5
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x
4
Tip!
A direct variation is a proportional relationship with an equation in the form
y = kx, where k is a fixed number other than zero. A straight line through the
origin (0,0) always represents a direct variation between y and x.
Analysis
1
A. Choice A is correct. This graph represents the equation y = 3 x, so y varies
directly with x. Notice that the graph is a straight line through the origin.
B. Choice B is incorrect. This graph can be eliminated because it does not go
through the origin.
C. Choice C is incorrect. This graph can be eliminated because it does not go
through the origin.
D. Choice D is incorrect. This graph can be eliminated because it does not go
through the origin.
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4
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7.NS.A.1c
Subtract Rational Numbers
Mathematics Flash Cards for Grade 7
22. The thermometer to the right shows the
temperature on Monday morning. By Tuesday the
temperature dropped eight degrees.
40° F
35° F
30° F
25° F
20° F
What would the temperature be on Tuesday
morning?
15° F
10° F
5° F
0° F
A.
−8°F
B.
−3°F
-15° F
C.
3°F
-25° F
D.
8°F
-35° F
-5° F
-10° F
-20° F
-30° F
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22
Analysis
A. Choice A is incorrect. The temperature dropped 8°F, but it did not start at
0°F.
B. Choice B is correct. Count 8 markings down from the beginning
temperature of 5°F, or subtract to find the answer: 5°F − 8°F = −3°F.
C. Choice C is incorrect. Recheck your work.
D. Choice D is incorrect. The temperature dropped 8°F.
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22
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7.EE.B.4b
Graph Inequalities
52.
Mathematics Flash Cards for Grade 7
Ant lizards live in the Sahara Desert, where temperatures are often above
100 degrees. The ant lizards can withstand the heat until the temperature
climbs too high. At this point the ant lizards hide in their burrows until the
temperature cools down again.
In the equation x − 16 ≥ 100, x represents the temperature at which the lizards
will be found in their burrows. Which of the following is the best graphical
representation of this equation?
A.
B.
96
104 112
116 120
100 108
108 116
112120
10096 104
C.
96
104 112
116 120
100 108
108 116
112120
10096 104
96
104 112
116 120
100 108
108 116
112120
10096 104
D.
96
104 112
116 120
100 108
108 116
112120
10096 104
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52
Analysis
A. Choice A is incorrect. The graph shows that the temperature of the desert is
often 100 degrees and higher, but it does not answer the question regarding
when the lizards are found in their burrows.
B. Choice B is correct. Ant lizards will be found in their burrows when the
temperature is equal to or greater than 116 degrees.
C. Choice C is incorrect. It shows that the lizards will only be found in their
burrows at temperatures above, but not equal to, 116 degrees.
D. Choice D is incorrect. It shows that the temperature is 116 degrees or lower,
which is not true according to the information given about the ant lizards.
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52
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7.SP.A.2
Use Data to Make Inferences
Mathematics Flash Cards for Grade 7
78. The table to the right summarizes the
average percentage of people in the
United States having each of the eight
common human blood types. If a blood
bank in a large U.S. city receives 8,325
blood donations, approximately how
many of these donations would you
expect to be B negative (B−)? Assume
the donors are a random sample of U.S.
racial and ethnic groups.
A.
14
C.
783
B.
142
D.
1415
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Blood Type
O+
OA+
AB+
BAB+
AB-
Percentage
in Population*
38.4%
7.7%
32.3%
6.5%
9.4%
1.7%
3.2%
0.7%
*Average for entire U.S. population. Distribution is
different for every racial and ethnic group.
Source: http://www.bloodbook.com/type-facts.html
78
Analysis
A. Choice A is incorrect. This is the result of multiplying 8,325 by 0.0017;
1.7% is 0.017, not 0.0017.
B. Choice B is correct. If the donors are a truly random sample of U.S. racial
and ethnic groups, then the distribution of human blood types among them
should be relatively close to the U.S. averages summarized in the table.
The table shows that 1.7% of Americans have B negative blood. This is the
same percentage we should expect from the donor sample: 1.7% = 0.017;
0.017 × 8,325 ≈ 142 people in the sample have B− blood.
C. Choice C is incorrect. Recheck your calculations.
D. Choice D is incorrect. This is the result of multiplying 8,325 by 0.17; 1.7%
is 0.017, not 0.17.
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78