Page 130 - Start Up Mathematics_5

9

Time, Temperature and

Money

Let’s Recall …

• There are two types of clocks—12-hour clock and 24-hour clock.
• Time from 12 o’clock at night (midnight) to 12 o’clock at noon is expressed
as a.m. (morning).

• Time from 12 o’clock at noon to 12 o’clock midnight is expressed as p.m. (evening/night).
• The format of a 24-hour clock is hours:minutes or hours:minutes:seconds.
• 1 hour = 60 minutes

• ` 1 = 100 paise

1 Rewrite the following statements using a.m. or p.m.

(a) Sneha started doing her homework at 5:30 in the evening.
(b) Dr Pathak left for his clinic at 8 o’clock in the morning.

2 Convert as directed.

(a) 16 minutes to seconds (b) 2 hours 35 minutes to seconds
(c) ` 18.75 to paise (d) 46 paise to rupees
(e) 3:15 p.m. to 24-hour time (f) 16:40 to 12-hour time

3 Add 3 hours 20 minutes and 5 hours 25 minutes.

4 Subtract 7 h 25 min from 11 h 40 min.

5 What is the duration of time between 7 p.m. to 6 a.m.?

Addition, Subtraction and Multiplication of Time

Example 1: Add 8 hours 35 minutes and 7 hours 45 minutes.

Solution: h min
1
8 3 5 Remember
+ 7 4 5
1 h When the number of
1 5 8 0 is more than 60 minutes minutes is more than 60,
we subtract 60 from it and
– 6 0 (1 h) carry over 1 to hours.
1 6 2 0

So, 8 h 35 min + 7 h 45 min = 16 h 20 min.

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