Measuring Elapsed Time Lesson 4 7 Units of
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Measuring Elapsed Time Lesson 4 -7
Units of Time • • • 1 minute (min) = 60 seconds (s) 1 hour (h) = 60 minutes 1 day = 24 h 1 week (wk) = 7 days 1 year is about 365 days 1 year is about 52 weeks
Equivalent Times 80 1 minute 20 seconds = _____s 1 min = 60 s + 20 s = 80 s 114 4 days 18 hours = _____h 4 days x 24 hours = 96 hours 96 h + 18 h = 114 h
Elapsed time • The time between two events is called elapsed time. • If both times are AM, or both times are PM, then just subtract the times. • Be careful when times pass midnight or noon.
Example: Find the elapsed time between 1: 45 PM and 5: 27 PM 5: 27 1: 45 4 87 5 h 27 min 1 h 45 min 3 h 42 min 1 h = 60 min
How long is a school day that goes from 8: 15 AM to 3: 25 PM? When one time is in the morning, and one is in the afternoon, add 12 hours to the end-time. This takes care of passing from AM to PM. 3 hours 25 min 15 hours 25 min 8 hours 15 min 7 hours 10 min
Counting Up Another way to deal with elapsed time that includes both AM and PM is to “count up. ” Add hours and minutes at the end. Example: How much time is between 5: 45 AM and 7: 20 PM? 5: 45 to 6: 00 15 min 6: 00 to 12: 00 6 h 12: 00 to 7: 00 7 h 7: 00 to 7: 20 20 min Combine minutes with minutes: 15 + 20 = 35 min Combine hours with hours: 6 + 7 = 13 h Answer: 13 hours and 35 minutes.
Homework Time
