Unit 4: Time and Measurement
Lesson 1: Two ways to write dates
Words and Numbers
Example: March 10th, 2014
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Metric Notation
Example: 10 03 2004 or 10 03 04
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Lesson 2: Telling Time on Analog Clock
How do we know this is 2:30?
- Hour first - How do we know the hour is 2? The short hand is on 2 or between 2 and 3.
- Minutes next. - How do we know it is 30? The long hand is at 30 minutes mark (at 6). (To figure out minutes, it helps to know that the numbers are actually multiple of 5s).
- So 2:30!
Lesson 3: Telling Time on Analog Clock with words
Lesson 4: Converting 12-hour time to 24-hour time
AM
24 Hour clock looks just like the AM time but must be 4 digits. Example: 1:00 AM = 01:00 2:00 AM = 02:00 10:00 AM = 10:00 Except for 12 AM ------- 12 AM is 0000 |
PM
For PM, you must ADD 12 hours to the PM time to get the 24 hour time. Example: 1:00 PM + 12:00 = 13:00 2:00 PM + 12:00 = 14:00 10:00 AM +12:00 = 22:00 Except for 12 PM ------- 12 PM is 1200 |
Lesson 5: Converting 24-hour time to 12-hour time
AM
AM time looks just like the 24 Hour time up to 1300. Example: 1:00 AM = 01:00 2:00 AM = 02:00 10:00 AM = 10:00 Except for 12 AM ------- 12 AM is 0000 |
PM
If the time is over 1200 or higher, it is PM. To find the PM time, just minus 12. Example: 13:54 - 12:00 = 1:54 PM 16:04 - 12:00 = 4:04 PM Except for 1200 ------- You don't have to minus. |
Lesson 6: Changing total minutes to hours and minutes
Long way
EXAMPLE: 260 minutes is how many hours and minutes? 1. 260 - 60 = 200 (200 can still minus 60 so minus again) 2. 200 - 60 = 140 (140 can still minus 60 so minus again) 3. 140 - 60 = 80 (80 can still minus 60 so minus again) 4. 80 - 60 = 20 (20 CANNOT minus 60 so we stop) 5. How many times did you - 60? 4 6. How many minutes are left? 20 So 260 minutes is equal to 4 hours and 20 minutes! |
Short way
How many times can 60 fit into 260? 4 times 60 = 240 What is the remainder? 20 minutes So the answer is 4 hours and 20 minutes. |
Lesson 7: Calculating Elapsed Time
Lesson 7: Determining End time
Example Problem: Henry started reading at 5:20. He read for 3 hours and 50 minutes. What time did he finish?
Step One
Find out the start time and elapsed time.
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Step Two
Add them together. 5 h 20m +3 h 50m 8 h 70m |
Step Three
But 70m is more than 60 m. So just add 1 to the hour and -60 from the minutes: 8h 70m --> 9:10 |
Lesson 8: Measuring area
Lesson 9: Estimating Area
Using the leaf on the right, I will show you the steps to estimate area.
1. Count all the whole squares - 3 square units 2. Count all the halves - 2 halves = 1 square unit 3. Count all the squares that are more than halves as 1 square = 4 square units 4. Do not bother with all the squares that are less than half = Always 0 Total for the leaf is 3 + 1 + 4 = 8 square units! |
Vocabulary
Quarter past ___
When telling time, 15 minutes after set hour. Ex. 5:15 is quarter past 5. |
Quarter to ____
When telling time, 15 minutes to set hour. Ex. 4:45 is Quarter to 5. |
Half past ____
When telling time, it is 30 minutes past a set hour. Ex. 5:30 is half past 5. |
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