7th Grade Math

4141 BOOK REPORTS Four students were scheduled to give book reports in a

1-hour class period. After the first report, _^2

3

hour remained. If the next two

students’ reports took _^1

6

hour and _^1

4

hour, respectively, what fraction of the

hour remained for the final student’s report? Justify your answer.

42. CELL PHONES One hundred sixty
    cell phone owners were surveyed.

3

8

)PX
EP
ZPV
VTF

B
DFMM
QIPOF

Taking

pictures

3

8

Text

messaging

1

4

Playing

games

What fraction of owners prefers

using their cell phone for text

messaging or taking pictures?

43. MEASUREMENT LaTasha and Colin are
    jogging on a track. LaTasha jogs _^14 of a

mile and then stops. Colin jogs _^58 of a

mile, stops, and then turns around and

jogs _^12 of a mile. Who is farther ahead

on the track? How much farther? Explain.

44. CHALLENGE Fractions whose numerators are 1, such as ^1
    2
    or ^1
    3
    C , are called
    unit fractions. Describe a method you can use to add two unit fractions
    mentally. Explain your reasoning and use your method to find 991 + 1001.


45. OPEN ENDED Provide a counterexample to the following statement.
    The sum of three fractions with odd numerators is never _^1
    2
    .


46. FIND THE ERROR Theresa is finding _^1
    4
    
    
    • _^3
      5
      .
      Find her mistake and correct it.
    
    
    
    

_^1

4

+ _^3

5

= _1 + 3

4 + 5

47. E WRITE MATH To make a cake, Felicia needs 1 cup of flour, but she
    only has a ^2
    3
    -cup measure and a ^3
    4
    -cup measure. Which method will
    bring her closest to having the amount of flour she needs? Explain.
    a. Fill the ^2
    3
    -cup measure twice. c. Fill the ^2
    3
    -cup measure once.

b. Fill the _^3

4

-cup measure twice. d. Fill the _^3

4

-cup measure once.

Real-World Link

The world’s largest

edible cupcake

weighed about

61 pounds and was

more than a foot tall.

This is 150 times the

size of a regular

cupcake!

RR

T

150 Rational Numbers

139_156_C3L2_895130.indd 150 12/31/09 12:37 PM