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# Kungfu math p4 slide17 (time)pdf

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### Kungfu math p4 slide17 (time)pdf

1. 1. Measurement TimeWhat will we learn today?• measurement of time in seconds (s)• 24-hour clock• solving word problems involving time in 24-hour clock
2. 2. Time is precious.Time is a measurement. We need to know the techniques, so that wecan tell time accurately.
3. 3. Adding and Subtracting Time1. We need to Add or Subtract the hours and minutes separately.But you may need to do some adjusting if theminutes end up 60 or more, or less than zero!We will be discussing more on this in the laterslides.
4. 4. Adding TimesFollow these simple steps:1. Add the hours.2. Add the minutes.3. If the minutes are 60 or more, subtract 60 from the minutes and add 1 to hours.
5. 5. Try this out!1. This is an easy example:What is 2:45 + 1:05?Add the Hours: 2+1 = 3Add the Minutes: 45+5 =50The minutes have not exceeded 60,so the answer is 3:50
6. 6. Try this out!2. This is a hard example:What is 2:45 + 1:25 ?Add the Hours: 2+1 = 3Add the Minutes: 45+25 = 70The minutes are 60 or more, so we have tosubtract 60 from minutes (70-60 = 10 Minutes)and add 1 to Hours (3+1 = 4 Hours)So, the answer is 4:10
7. 7. Subtracting TimesFollow these simple steps:1. Subtract the hours.2. Subtract the minutes.3. If the minutes are negative, add 60 to the minutes and subtract 1 from hours.
8. 8. Subtracting Times1. This is an easy example:What is 4:10 - 1:05 ?Subtract the Hours: 4-1 = 3Subtract the Minutes: 10-5 = 5The minutes have not become negative ,so the answer is 3:05
9. 9. Subtracting Times2. This is a hard example:What is 4:10 - 1:25 ?Subtract the Hours: 4-1 = 3Subtract the Minutes: 10-25 = -15The minutes are less than 0, so we have toadd 60 to Minutes(-15+60 = 60-15 = 45 Minutes) andsubtract 1 from Hours (3-1 = 2 Hours)So, the answer is 2:35
10. 10. Try this out!The Chan family set off for the zoo at 08 00.They drove for 45 minutes and stopped forbreakfast at a coffee shop.They ate for 1 h and it took them another45 minutes to reach the zoo.They left the zoo at 17 00.How long did they stayat the zoo?Give your answers in hours and minutes.
11. 11. Let’s do it step by step!The Chan family set off for the zoo at 08 00. 0800
12. 12. Let’s do it step by step!The Chan family set off for the zoo at 08 00.They drove for 45 minutes and stopped forbreakfast at a coffee shop. 0800 0845 45 minutes
13. 13. Let’s do it step by step!The Chan family set off for the zoo at 08 00.They drove for 45 minutes and stopped forbreakfast at a coffee shop.They ate for 1 h 0800 0845 0945 45 minutes 1 hour
14. 14. Let’s do it step by step! The Chan family set off for the zoo at 08 00. They drove for 45 minutes and stopped for breakfast at a coffee shop. They ate for 1 h and it took them another 45 minutes to reach the zoo.0800 0845 0945 1030 45 minutes 1 hour 45 minutes
15. 15. Let’s do it step by step!The Chan family set off for the zoo at 08 00.They drove for 45 minutes and stopped for breakfastat a coffee shop.They ate for 1 h and it took them another45 minutes to reach the zoo. They left the zoo at 17 00. 1030 1700 ?They reached the zoo at 1030.
16. 16. How long did they stay at the zoo? 1030 1100 1200 1300 1400 1500 1600 1700Let’s count backwards
17. 17. How long did they stay at the zoo? 1030 1100 1200 1300 1400 1500 1600 1700 6 hours
18. 18. How long did they stay at the zoo? 1030 1100 1200 1300 1400 1500 1600 170030 minutes 6 hours
19. 19. How long did they stay at the zoo? 1030 1100 1200 1300 1400 1500 1600 170030 minutes 6 hours 6 hours 30 minutes
20. 20. Are you ready to try out the questions?
21. 21. Visit kungfumath.sg today!