TIME
Time – “what a clock reads”. Clocks measure time.
Time is the ongoing sequence of events: Past, Present and Future.
Usually, time is shown as Hours:Minute
SYMBOL
Hour: h Minute: min Second: s
READING THE MARK
The minute hand takes 5 minutes to move from 1 number to the next.
TELLING TIME
a.m : Ante Meridiem (Latin for “before midday”)
p.m.: Post Meridiem (Latin for “after midday”)
1 h = 60 mins
½ h = 30 mins
COMMONLY USED TERMS
LATER, AFTER, PAST: “ADD” to the given time
Example:
What time is 1 h after 12 noon?
12noon is 12pm, add 1h - > 1 pm
Example:
What time is 20 minutes past 4 in the afternoon?
20 minutes after 4pm is 4pm + 20 min -> 4:20pm
Example:
It is 4:30pm now. What is 20minutes later?
4:30pm + 20min -> 4:50pm
BEFORE, TO: “SUBTRACT” from the given time
Example:
What time is 10minutes before 14 45?
10 minutes before 14 45, MINUS 10 mins from 45mins -> 14 35
-> 14 35 is 10 before 14 45
Example:
What time is 15minutes to 9:30a.m.?
15 minutes before 9:30a.m. is 9:15a.m.
-> 9:15a.m. is 15 minutes before 9:30am
ADD / SUBTRACT TIME
1h = 60 minutes
Adding Hours and Minutes
Example
What is 1h 45min + 2h 50mins
Method
Step1: Add hour and mins separately
1h + 1h = 2h
45mins + 50mins = 95mins
Step2: If min is 60 or more, minus 60mins and change to 1h
95-60 = 35 -> 95mins = 1h 35mins
Step3: Solve: Add hours (if need be)
2h + 1h = 3h
Answer = 3h 35min
Subtracting Hours and Minutes
Example
What is 4h 20min - 2h 50mins?
Method
Step1: Compare Minutes. If “1st” minute is less than “2nd”, change 1h to 60min
20min is less than 50min, “change” 1h -> 4h = 3h +60min
20min + 60min = 80min.
Step2: Compute minutes
80min – 50min = 30min
Step3: Solve:
3h – 2h = 1h
Answer = 1h 30mins
DURATION, START TIME, END TIME
DURATION
DURATION
~ starting time till the ending time of an event or task.
Example
Ali went to bed at 10pm. He woke up at 6:30am. How long did he slept?
Method
Step1: Circle/Underline Keywords. Draw “Clock” or the time-line
[If the time across 12 midnight, draw the 12am mark]
Step2: Mark data. Compute Value
10pm -> 12 am = 2h
12am -> 6:30am = 6 ½h
Step3: Solve: Answer
Ali slept for 2h + 6½h = 8½h
Example
The Science lesson started at 2:15pm and ended at 4:30pm. How long was the lesson?
Method
Step1: Circle/Underline Keywords. Draw “Clock” or the time-line
Step2: Mark data. Compute Value
2:15pm -> 3pm = 45min or 4:30pm – 2:15pm
3pm -> 4:30pm = 1h 30min = 2h 15min
Step3: Solve: Answer
The lesson is 45 mins + 1h 30 mins = 2h15min
STARTING TIME
Example
Ginny runs for 45 min. she finished at 5pm. What time did she start running?
Step1: Circle/Underline Keywords. Draw time-line
Step2: Mark data. Compute Value. Arrow < --- ( - )
5pm – 45min 60min – 45min = 15min
= 4:15pm
Step3: Solve: Answer
She starts running at 4:15pm
ENDING/FINISHING TIME
Adam played game for 1h 30 min. The game started at 3pm. What time did the game end?
Step1: Circle/Underline Keywords. Draw time-line
Step2: Mark data. Compute Value. Arrow -à ( + )
3pm + 1h 30min
= 4:30pm
Step3: Solve: Answer
The game ended at 4:30pm.
CONVERTING HOURS, MINUTES, SECONDS
1 Hour = 60minutes
1 minute = 60 seconds
To
convert hour to min, multiply the hour value by 60
To convert min to hour, divide the minute value by 60
To convert min to hour, divide the minute value by 60
Method (using “time” table)
“Time” Converter
(Divide) / < --- h(60) : Min(60) : s(60) ---> x (Multiply)
DIVIDE : <---- Convert direction ----> MULTIPLY
Example:
Convert 4hr to minutes
Method
Step1 Circle keywords. Draw Converter
/ < --- h(60) : Min(60) : s(60) ---> x
Step2 Determine x or /
h - m -> x
Step3 Calculate: Put value at hour and multiply
h(4) : m(60) ---> x
4h = 4 x 60 = 240m
Example:
Convert 600sec to minutes
Method
Step1 Circle keywords. Draw Converter
/ < --- h(60) : Min(60) : s(60) ---> x
Step2 Determine x or /
s to min <- /
Step3 Calculate: Put value at hour and multiply
/ < --- m(600) : m(60)
600s = 600/60 = 10min
~~~~ END ~~~~ :)
Example
Write 1h 32 min in minutes
Step1 Circle keywords. Draw Converter
[in minutes -> no change to 32 min]
/ < --- h(60) : Min(60) : s(60) ---> x
Step2 Determine x or /
h to min ---> x
Step3 Calculate: Put value at hour and multiply
h(1) : m(60) ---> x
1h = 1 x 60 = 60min
1h 32min = 60min + 32 min = 92 mins
Example
Write 90 minutes in hours and minutes
Step1 Circle keywords. Draw Converter
/ < --- h(60) : Min(60) : s(60) ---> x
Step2 Determine x or /
min to h <- /
Step3 Calculate: Put value at hour and multiply
/ < --- h(90) : m(60)
90m = 90/60 = 60/60 h + 30min
= 1h 30min
Time Vocabulary
1. O’clock 2. Midnight 3. Morning
4. Noon 5. Afternoon 6. Night
7. a.m. 8. p.m. 9. Hour
10. Minutes 11. Seconds 12. Earlier
13. Later 14. Before. 15. After
16. Minutes past 17. Minutes to 18. Quarter past
19. Quarter to 20. Half past 21. Clockwise
22. Anti-clockwise 23. Starting time 24. Finishing time
25. Duration
