1. Splash Screen

2. Lesson Menu Five-Minute Check (over Lesson 8–6) Main Idea and Vocabulary Key Concept: Units of Time Example 1:Add Units of Time Example 2:Subtract Units of Time Example 3:Subtract Units of Time to Solve a Problem Example 4:Elapsed Time

3. Main Idea/Vocabulary elapsed time Add and subtract measures of time.

4. KC 1

5. Example 1 Add Units of Time Find the sum of 3 h 15 min 52 s and 1 h 42 min 11 s. Estimate3 h 15 min 52 s + 1 h 42 min 11 s ≈ 3 h + 2 h or 5h Add seconds first, then minutes, and finally hours. 3 h 15 min 52 s 63 seconds is greater than 60 seconds or 1 minute. + 1 h 42 min 11 s 4 h 57 min 63 s

6. Example 1 Add Units of Time 4 h 57 min (1 min 3 s)Rename 63 seconds as 1 minute and 3 seconds. Answer: So, the sum is 4 hours 58 minutes 3 seconds. 4h 58 min 3s ≈ 5h 4 h 58 min 3 sAdd minutes.

7. 1.A 2.B 3.C 4.D Example 1 A.7 h 30 min 8 s B.7 h 48 min 49 s C.7 h 49 min 48 s D.8 h 8 min 29 s Find the sum of 2 h 18 min 37 s and 5 h 31 min 11 s.

8. Example 2 Subtract Units of Time Find the difference of 5 h 35 min 29 s and 2 h 51 min 10 s. Estimate5 h 35 min 29 s – 2 h 51 min 10 s ≈ 5.5 h – 3 h or 2.5 h 5 h 35 min 29 s – 2 h 51 min 10 s 19 s Subtract the seconds first. Notice that you cannot subtract 51 minutes from 35 minutes. (4 h 60 min)35 min 29 s – 2 h 51 min 10 s 19 s Rename 5h as 4 h + 1 h or 4h 60 min.

9. Example 2 Subtract Units of Time Check for Reasonableness2 h 44 min 19 s ≈ 2.5 h Answer: 2h 44 min 19 s 4 h 95 min 29 s – 2 h 51 min 10 s 19 s Add the minutes. 4 h 95 min 29 s – 2 h 51 min 10 s 2 h 44 min 19 s Subtract the minutes, then the hours.

10. 1.A 2.B 3.C 4.D Example 2 A.3 h 29 min 21 s B.3 h 31 min 21 s C.4 h 29 min 21 s D.4 h 31 min 21 s Find the difference of 7 h 16 min 45 s and 3 h 45 min 24 s.

11. Example 3 MARATHONS The table shows the times of the winners of the men’s and women’s races at the 2007 Boston Marathon. How much faster was Cheruiyot’s time than Grigoyeva’s time? Estimate2 h 29 min 18 s – 2 h 14 min 13 s ≈ 29 min – 14 min or 15 min Subtract Units of Time to Solve a Problem

12. Example 3 2 h 29 min 18 sSubtract the seconds first, then –2 h 14 min 13 sminutes, and finally hours. 15 min 5 s Answer: Cheruiyot’s time was 15 minutes 41 seconds faster than Grigoyeva’s time. Subtract Units of Time to Solve a Problem Check for Reasonableness15 min 5 s ≈ 15 min

13. 1.A 2.B 3.C 4.D Example 3 A.14 min 8 s B.14 min 52 s C.15 min 8 s D.15 min 52 s Jeremy ran a local marathon in 2 hours 53 minutes 47 seconds. His best friend Sam ran the same marathon in 2 hours 38 minutes 55 seconds. How much faster did Sam run?

14. Example 4 Elapsed Time MOVIES A movie begins at 2:45 P.M. and ends at 4:22 P.M. How long is the movie? You need to find out how much time has elapsed. 2:45 P.M. to 3:00 P.M. is 15 minutes. 3:00 P.M. to 4:22 P.M. is 1 hour 22 minutes.

15. Example 4 Elapsed Time 15 min + 1 h 22 min Answer: The length of the movie is 1 hour 37 minutes. 1 h 37 min Add the elapsed time before 3:00 and the elapsed time after 3:00 to find the total elapsed time.

16. 1.A 2.B 3.C 4.D Example 4 A.1 h 25 min B.1 h 35 min C.2 h 5 min D.2 h 35 min BUSES A bus leaves the station at 6:45 A.M. If it arrives at its destination at 8:10 A.M., how long was its trip?

17. End of the Lesson

18. Resources Five-Minute Check (over Lesson 8–6) Image Bank Math Tools Length in the Customary System The Metric System

19. 1.A 2.B 3.C 4.D Five Minute Check 1 (over Lesson 8-6) A.0.0002 B.0.002 C.0.02 D.0.2 Complete. 20 m = _____ km

20. 1.A 2.B 3.C 4.D Five Minute Check 2 (over Lesson 8-6) A.1,000,000 B.100,000 C.10,000 D.1,000 Complete. 100 L = _____ mL

21. 1.A 2.B 3.C 4.D Five Minute Check 3 (over Lesson 8-6) A.4.5 B.0.45 C.0.045 D.0.0045 Complete. 45 mg = _____ g

22. 1.A 2.B 3.C 4.D Five Minute Check 4 (over Lesson 8-6) A.30 B.300 C.3,000 D.30,000 Complete. 0.3 km = _____ m

23. 1.A 2.B 3.C 4.D Five Minute Check 5 (over Lesson 8-6) A.0.045 meters B.0.45 meters C.450 meters D.4,500 meters The nearest town is 4.5 kilometers away. How far is that in meters?

24. 1.A 2.B 3.C 4.D Five Minute Check 6 (over Lesson 8-6) A.60,000 B.600,000 C.6,000,000 D.60,000,000 A truck has a mass of 6,000 kilograms. How many grams does the truck weigh?

25. End of Custom Shows