Chapter review

Show your thinking; use diagrams when they help. Do not open solutions during your first attempt.

1. A1

   Express 31 days in weeks and days.

   Reveal explanation

   Answer: 4 weeks 3 days

   One week is seven days. 31 = 7 × 4 + 3.

2. A2

   How many minutes pass from 12:45 p.m. to 1:10 p.m.?

   Reveal explanation

   Answer: 25 min

   Count from 12:45 p.m. to the next whole hour, then onward to 1:10 p.m.. The intervals add to 25 minutes.

3. A3

   A lesson begins at 10:45 a.m. and lasts 35 minutes. When does it finish?

   Reveal explanation

   Answer: 11:20 a.m.

   Add 35 minutes to the start time, crossing each next hour carefully. 10:45 a.m. plus 35 minutes is 11:20 a.m..

4. A4

   How many minutes pass from 11:15 p.m. to 12:20 a.m.?

   Reveal explanation

   Answer: 65 min

   Count from 11:15 p.m. to the next whole hour, then onward to 12:20 a.m.. The intervals add to 65 minutes.

5. A5

   A student leaves at 6:50 a.m., walks 25 minutes, then studies 55 minutes. At what time does studying end?

   Reveal explanation

   Answer: 8:10 a.m.

   First reach 7:15 a.m. after walking, then add 55 minutes. Finish at 8:10 a.m..

6. A6

   Convert 1 h 35 min into minutes.

   Reveal explanation

   Answer: 95 min

   Each hour is 60 minutes. 1 × 60 + 35 = 95 minutes.

7. A7

   How many minutes pass from 9:10 a.m. to 9:35 a.m.?

   Reveal explanation

   Answer: 25 min

   Count from 9:10 a.m. to the next whole hour, then onward to 9:35 a.m.. The intervals add to 25 minutes.

8. A8

   A lesson begins at 9:25 a.m. and lasts 90 minutes. When does it finish?

   Reveal explanation

   Answer: 10:55 a.m.

   Add 90 minutes to the start time, crossing each next hour carefully. 9:25 a.m. plus 90 minutes is 10:55 a.m..

9. A9

   How many minutes pass from 11:15 p.m. to 12:45 a.m.?

   Reveal explanation

   Answer: 90 min

   Count from 11:15 p.m. to the next whole hour, then onward to 12:45 a.m.. The intervals add to 90 minutes.

10. A10

    A student leaves at 9:55 a.m., walks 15 minutes, then studies 55 minutes. At what time does studying end?

    Reveal explanation

    Answer: 11:05 a.m.

    First reach 10:10 a.m. after walking, then add 55 minutes. Finish at 11:05 a.m..

11. A11

    Express 215 minutes in hours and minutes.

    Reveal explanation

    Answer: 3 h 35 min

    There are 3 full groups of 60 minutes and 35 more minutes.

12. A12

    How many minutes pass from 12:55 p.m. to 2:00 p.m.?

    Reveal explanation

    Answer: 65 min

    Count from 12:55 p.m. to the next whole hour, then onward to 2:00 p.m.. The intervals add to 65 minutes.

13. A13

    A lesson begins at 8:10 a.m. and lasts 25 minutes. When does it finish?

    Reveal explanation

    Answer: 8:35 a.m.

    Add 25 minutes to the start time, crossing each next hour carefully. 8:10 a.m. plus 25 minutes is 8:35 a.m..

14. A14

    How many minutes pass from 10:50 a.m. to 12:05 p.m.?

    Reveal explanation

    Answer: 75 min

    Count from 10:50 a.m. to the next whole hour, then onward to 12:05 p.m.. The intervals add to 75 minutes.

15. A15

    A student leaves at 7:05 a.m., walks 25 minutes, then studies 55 minutes. At what time does studying end?

    Reveal explanation

    Answer: 8:25 a.m.

    First reach 7:30 a.m. after walking, then add 55 minutes. Finish at 8:25 a.m..

16. A16

    Convert 1 min 5 s into seconds.

    Reveal explanation

    Answer: 65 s

    Each minute contains 60 seconds. 1 × 60 + 5 = 65 seconds.

17. A17

    How many minutes pass from 1:50 p.m. to 2:15 p.m.?

    Reveal explanation

    Answer: 25 min

    Count from 1:50 p.m. to the next whole hour, then onward to 2:15 p.m.. The intervals add to 25 minutes.

18. A18

    A lesson begins at 11:40 a.m. and lasts 25 minutes. When does it finish?

    Reveal explanation

    Answer: 12:05 p.m.

    Add 25 minutes to the start time, crossing each next hour carefully. 11:40 a.m. plus 25 minutes is 12:05 p.m..

19. A19

    How many minutes pass from 11:35 a.m. to 1:25 p.m.?

    Reveal explanation

    Answer: 110 min

    Count from 11:35 a.m. to the next whole hour, then onward to 1:25 p.m.. The intervals add to 110 minutes.

20. A20

    A student leaves at 1:20 p.m., walks 15 minutes, then studies 35 minutes. At what time does studying end?

    Reveal explanation

    Answer: 2:10 p.m.

    First reach 1:35 p.m. after walking, then add 35 minutes. Finish at 2:10 p.m..

21. A21

    Express 85 seconds in minutes and seconds.

    Reveal explanation

    Answer: 1 min 25 s

    Group the 85 seconds into complete 60-second minutes, then count the 25 remaining seconds.

22. A22

    How many minutes pass from 1:50 p.m. to 2:40 p.m.?

    Reveal explanation

    Answer: 50 min

    Count from 1:50 p.m. to the next whole hour, then onward to 2:40 p.m.. The intervals add to 50 minutes.

23. A23

    A lesson begins at 2:15 p.m. and lasts 50 minutes. When does it finish?

    Reveal explanation

    Answer: 3:05 p.m.

    Add 50 minutes to the start time, crossing each next hour carefully. 2:15 p.m. plus 50 minutes is 3:05 p.m..

24. A24

    How many minutes pass from 11:40 p.m. to 12:45 a.m.?

    Reveal explanation

    Answer: 65 min

    Count from 11:40 p.m. to the next whole hour, then onward to 12:45 a.m.. The intervals add to 65 minutes.

25. A25

    A trip begins at 11:45 p.m. and lasts 45 minutes. On which day does it finish and at what time?

    Reveal explanation

    Answer: Next day at 12:30 a.m.

    15 minutes reach midnight; 30 minutes more reach 12:30 a.m. on the next day.

26. A26

    Why is 7 hours 15 minutes not 715 minutes?

    Reveal explanation

    Answer: 435 minutes

    Each hour has 60 minutes, so 7 hours 15 minutes is 420+15=435 minutes.