The elevation of Death Valley, California, is -282 feet. The elevation of Tallahassee, Florida, is 203 feet. The elevation of Westmorland, California, is -157 feet.
Label each point on the number line with the name of the city whose elevation is represented by the point.
Use the symbol < or > to compare the elevations of Death Valley and Tallahassee.
Use the symbol < or > to compare the elevations of Death Valley and Westmorland.
Show Solution
A: Death Valley, California
B: Westmorland, California
C: Tallahassee, Florida
Andre looks at a box of paper clips. He says: “I think the number of paper clips in the box is less than 1,000.”
Lin also looks at the box. She says: “I think the number of paper clips in the box is more than 500.”
Write an inequality to show Andre's statement, using p for the number of paper clips.
Write another inequality to show Lin's statement, also using p for the number of paper clips.
Do you think both Lin and Andre would agree that there could be 487 paperclips in the box? Explain your reasoning.
Do you think both Lin and Andre would agree that there could be 742 paperclips in the box? Explain your reasoning.
Show Solution
p<1,000
p>500
No. Sample reasoning: Andre would agree because the inequality, 487<1,000 is a true statement. However, Lin would not agree because the inequality 487>500 is a false statement.
Yes. Sample reasoning: Both inequalities are true for 742 paper clips: 742<1,000, and 742>500. This means that according to Lin and Andre, there could be 742 paperclips in the box.
Lin says that the inequalities h>150 and h<160 describe her height in centimeters. What do the inequalities tell us about her height?
Andre notices that he is a little taller than Lin but is shorter than their math teacher, who is 164 centimeters tall. Write two inequalities to describe Andre's height. Let a be Andre's height in centimeters.
Select all heights in centimeters that could be Andre's height. If you get stuck, consider drawing a number line to help you.
150
154.5
160
162.5
164
Show Solution
These inequalities tell us that Lin is between 150 and 160 cm tall.
a<164 and a>h (or h<a).
B, C, D
Section B Check
Section B Checkpoint
Problem 1
A medication has to be stored at a temperature less than 10 degrees Celsius.
Let t be the temperature. Write an inequality that describes the safe storage temperature for the medication.
Draw a number line to represent solutions to the inequality.
Show Solution
t<10
Problem 2
Select all the numbers that are solutions to n>-3.
Here are the scores for landing an arrow in the different regions of the archery target.
A: 10 points
B: 8 points
C: 6 points
D: 4 points
E: 2 points
Andre shot three arrows and they landed at (-5,4),(-8,7) and (1,6). What is his total score? Explain or show your reasoning.
Jada shot an arrow and scored 10 points. She shot a second arrow that landed directly below the first one but scored only 2 points. Name two coordinates that could be the landing points of her two arrows.
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14 points. Sample reasoning: (-5,4) is 6 points, (-8,7) is 8 points, and (1,6) is 0 points.
Lin labeled this set of axes and plotted the points A(1,2), B(-3,-5), C(5,7), D(-4,-3), and E(-4,6) in the coordinate plane.
Identify as many mistakes as you notice in Lin's graph.
Coordinate plane, horizontal axis, negative six to 5 by ones, vertical axis, negative 5 to 10 by ones. Point A is 1 point right and 2 points up from the origin. Point B is 3 units left and 5 units down from the origin. Point C is 5 points right and 8 points up from from the origin. Point D is 3 points left and 4 points down from the origin. Point E is 4 points left and 3 points up from the origin.
Show Solution
Point C is plotted at (5,8) instead of (5,7). Point D is plotted at (-3,-4) instead of (-4,-3).
What is the greatest common factor of 24 and 64? Explain or show your reasoning.
In your own words, what is the greatest common factor of two whole numbers? How can you find it?
Show Solution
8. Sample reasoning: The common factors of 24 and 64 are 1, 2, 4, and 8, and 8 is the greatest.
Sample response: The greatest common factor of two whole numbers is the largest number that divides evenly into both numbers. You can find the greatest common factor by listing the factors of each number and then finding the greatest one that both numbers share.
What is the least common multiple of 6 and 9? Explain or show your reasoning.
In your own words, what is the least common multiple of two whole numbers? How can you find it?
Show Solution
The least common multiple of 6 and 9 is 18. Sample reasoning: The first few multiples of 6 are 6, 12, 18, 24, 30, and 36. The first few multiples of 9 are 9, 18, 27, and 36. The number 18 is the first to appear on both lists.
Sample response: The least common multiple of two numbers is the smallest multiple that the numbers share. You can find the least common multiple by listing the multiples of each number until you find one that is common to both lists. The first multiple that is common to both lists is the least common multiple.
For each problem, tell whether finding the answer requires finding a greatest common factor or a least common multiple. You do not need to solve the problems.
Elena has 20 apples and 35 crackers. She wants to make as many snack bags as possible that each contain the same combination of apples and crackers. What is the largest number of snack bags she can make?
A string of lights flashes two colors—red every 5 seconds and blue every 3 seconds. How long before both lights flash at the same time?
A florist orders sunflowers every 6 days and daisies every 4 days. On which day will she order both kinds of flowers on the same day?
Show Solution
Greatest common factor
Least common multiple
Least common multiple
Section D Check
Section D Checkpoint
Problem 1
Jada buys 30 tulip bulbs and 40 daffodil bulbs. Her plan is to plant all the bulbs in groups. She wants the groups to be identical and each group to have both types of flowers.
List three different ways Jada can group the flowers.
Show Solution
Sample responses:
1 group with 30 tulips and 40 daffodils
2 groups, each with 15 tulips and 20 daffodils
5 groups, each with 6 tulips and 8 daffodils
10 groups, each with 3 tulips and 4 daffodils
Problem 2
Pencils are sold in packages of 12, and erasers are sold in packages of 9. Kiran wants to buy the same number of erasers as pencils.
Find a number of pencils and erasers that will meet Kiran’s requirement. How many packages of pencils and how many packages of erasers will Kiran need to buy?
Find a different number of pencils and erasers that also meets Kiran’s requirement. Explain your reasoning.
Show Solution
Sample response: Kiran can have 36 pencils and 36 erasers if he buys 3 packages of pencils and 4 packages of erasers. (Any multiple of 36 pencils and erasers is also correct.)
Sample response: Kiran could also have 72 pencils and 72 erasers if he bought 6 packages of pencils and 8 packages of erasers.