Unit 7 Contents

Check-In: Questions 21–22

21. First find the values of the following expressions without a calculator. Then use a calculator to check your work.
1. 3 (12 −
   6) =
2. 3 12 −
   6 =
3. (6 + 3) (5 −
   2) =
4. 6 + 3 5 −
   2 =
5. 16 ÷ 4 −
   2 =
6. 16 ÷ (4 −
   2) =
7. 100 ÷ 10 −
   5 =
8. 100 ÷ (10 −
   5) =

 

22. Ana's group collected data for the lab Distance vs. Time. Jerome was the walker. He walked along a track, and the rest of the group reported the time he took to walk 6 yards, 9 yards, and 12 yards. Ana was the timer at 6 yards. On the first trial she didn't know how to use the stopwatch. Here is the first row of their data table:

1. Find the mean value of the three trials. Write a number sentence using parentheses to show how to find the mean.
2. Find the median value of the three trials.
3. Which average, the median or the mean, represents the data better? Explain your reasoning.