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2. Convert the following into minutes and seconds.
( a) 1318 seconds (b) 3165 seconds

3. Convert the following into hours and minutes.
( a) 238 minutes (b) 498 minutes (c) 1032 minutes (d) 3024 minutes

4. Convert the following into days and hours.
( a) 57 hours (b) 537 hours (c) 953 hours (d) 1810 hours

5. Convert the following using a double number line:
× 3
1 h __ h 7 h 12 h ___ h 16 h ___ h ___ h

× 60

60 min 180 min ___ min ___ min 840 min ___ min 1200 min 1380 min
× __

ADDiTiOn AnD sUBTRACTiOn Of mEAsUREs Of TimE

We can perform operations on time units as we did for length, weight and for capacity.

To perform addition or subtraction of time, we arrange the same units of time in the same
columns and then add or subtract.

Example 1: Add the following: Be Aware
( a) 32 minutes 48 seconds + 16 minutes 56 seconds We use ‘h’ for ‘hours’,
‘min’ for ‘minutes’, ‘s’ for
( b) 6 hours 34 minutes + 8 hours 47 minutes seconds for writing the

Solution: units of time in short form.
( a) Step 1: Add seconds:
48 seconds + 56 seconds = 104 seconds

= 60 seconds + 44 seconds = 1 minute 44 seconds min s
1
Step 2: Add minutes: 32 48
+ 16 56
1 minute + 32 minutes + 16 minutes = 49 minutes 49 44

Thus, 32 minutes 48 seconds + 16 minutes 56 seconds

= 49 minutes 44 seconds.
( b) Step 1: Add minutes:

34 minutes + 47 minutes = 81 minutes h min

81 minutes = 60 minutes + 21 minutes 1
= 1 hour 21 minutes ( 1 hour = 60 minutes) + 6 34
47
8
Step 2: Add hours: 15 21
1 hour + 6 hours + 8 hours = 15 hours
Thus, 6 hours 34 minutes + 8 hours 47 minutes = 15 hours 21 minutes.

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