Time 12/24 hour time, time intervals Distance, speed and time Return to Main Menu

Time L’heure Die Uhr

Time 1 L’heure 1 Die Uhr 1

Time may be expressed in 12 or 24 hour notation.

12-hour clock Time can be displayed on a clock face or a digital clock. These clocks both show fifteen minutes past five, or quarter past five. When writing times in 12 hour clock, we need to add a.m. or p.m. after the time. a.m. is used for times between midnight and 12 noon (morning). p.m. is used for times between 12 noon and midnight (afternoon / evening).

Time 2 L’heure 2 Die Uhr 2

24-hour clock In 24-hour clock, the hours are written as numbers between 00 and 24. Thus, midnight is expressed as 0000 or 2400. After 12 noon, the hours are numbered 13, 14, 15, etc …. Examples 9.55 am  0955 hours 3.35 pm  1535 hours 12.20 am  0020 hours 0216 hours  2.16 am 2045 hours  8.45 pm

A useful way of working out time problems is by using a time line. A programme started at 5:35 pm and finished at 7:25 pm. How long did it last? 5:35 6:00 7:00 7:25 25 mins + 1 hour + 25 mins = 1 hr 50 mins

In 1 year, there are: 365 days (366 in a leap year) 52 weeks 12 months It is essential to know the number of months, weeks and days in a year, and the number of days in each month. Time Facts In 1 year, there are: 365 days (366 in a leap year) 52 weeks 12 months The number of days in each month can be remembered using the rhyme: “30 days hath September, April, June and November, All the rest have 31, Except February alone, Which has 28 days clear, And 29 in each leap year.”

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Time 3 L’heure 3 Die Uhr 3

We can use a magic triangle to help us with distance, speed and time calculations. D S T Distance, Speed and Time. For any given journey, the distance travelled depends on the speed and the time taken. If speed is constant, then the following formulae apply: Distance = Speed x Time or D = S T Speed = Distance or S = D Time T Time = Distance or T = D Speed S Example Calculate the speed of a train which travelled 450 km in 5 hours S = D  450  S = 90 km/h T 5

Decimal Time Common errors are writing 2 hours and 30 minutes as 2.3 hours. To convert correctly to a decimal of an hour, divide the number of minutes by 60. E.g. 1 hour and 25 minutes = 1.42 hours to 2 decimal places (25 ÷ 60 = 0.41666...) To convert from a decimal of an hour, multiply the decimal part by 60. E.g. 3.75 hours = 3 hours and 45 minutes (0.75 × 60 = 45)

Don’t waste time. Work on it, now Don’t waste time! Work on it, now! Remember that you cannot turn back time!

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