LESSON 73 MEASURES TIME USING A 12-HOUR AND 24-HOUR CLOCK
Third Quarter
WEEK 7
Objective: Measuring time using a 12-hours and 24-hours clock
Value Focus : Cooperation/ accuracy
Prerequisite Concepts and Skills:
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Converting time between the 12 hours and 24 hours clock systems.
Read and write time according to the 12 hour / 24 hour system of time
Read and write the time in A.M. and P.M
Materials:
Clock, Activity sheet, picture, cartolina strips
References:
K-12 Grade 5 Curriculum Guide pp. 62
Code: M5ME-IIIg-14
Internet website www.mathenglish.com, / Mathisfun.com
Instructional Procedure:
A. Preliminary Activities
1. Drill
Write down all possible time using 12 hours.
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2. Review
How many hours in 1 day have?
According to the 12 hours clock system, each day is divided into two, how many
parts of 12 hours each?
3. Motivation:
Show a picture of a bus station. Have you been to a bus station ? What did you do
there? Share some of your experiences.
B. Developmental Activites
1. Presentation
Present the dialog in the class
In a bus station
Jessie:
What time that your friend arriving grandpa?
Grandpa : She said 5’o clock Jessie
Jessie:
And what is the time right now?
Grandpa: It is 5 minutes to 5 Jessie
Jessie:
ok grandpa! Hey grandpa, are these clock in
this station not working? What kind of time is
17:00 ?
Grandpa: No Jessie Here is 5 but it took like stop working
Jessie:
oh no
Grandpa: Here is an idea. There is a clock store right
outside the station. Why don’t you dare my
word over there and that is fix while I meet my
friend to arrive
Jessie:
ok grandma.
Jessie:
At the clock store
17 again? How can all the clock in station be
faulty, maybe someone in the clock store will be
even to help me.
Ask: What are they talking about while there are in the bus station ?
What was Jessie noticed about the time clock in the station?
What were his grandpa advice to Jessie ?
12 hours Clock System
Ante-meridian
Post- meridian
24 Hours Clocks System
H
H
HOURS
H
H
MINUTES
In 24 hours clock system, time is written as the number hours that have passed since
midnight. In the 24 hours system the day is not divided into 2 parts of 12 hours each but
it’s a continues periods of 24 hours. The 24 hours system of time written in 4 digits.
2. Performing the Activity
Lets help Jessie find the answer in his problem.
Lets the pupils work by pairs. Give them enough time to answer the activity. Let the
pupils show and explain their findings.
In the 24 hours system of time –time starts at 12 o’clock midnight 00.00 (zero hour )
1 am
0100 hours 2 am
0200 hours 4 am
0400 hours
- In 4:30 am ,how could it write that in 24 hours time format ?
- What time is it in the 24 hours format when it is 8:15 pm?
- What is the equivalent time of 17.24 in the 12 Hours Clock System ?
3. Processing the Activity
A. Let the pupils present their answer
Ask: How did you find the answer?
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5:30 a.m. in a 12 hours clock system will be written as 05.30 (5 and 30 hours) in the 24
hours clock system.
(In 24 hours clock system, the time is written in 4 digits)
9:15 p.m. in a 12 hours clock system will be 21.15 (20 and 15 hour) in the 24 hours clock
system.
(In transforming 12 hours time format to 24hours time format add 12 to the hours and
keep the minute same.)
17:24 time is the equivalent of 5:24 time in the 12 hours clock system.
( In transforming 24 hours time format to 12 hours time format subtract 12 from the
hours and keep the minute same )
B. Let’s the pupils to answer the following question:
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24 Hours Riddles 1 answers
CHALLENGE A
I am between 8:00 and 14:30
I am less than 20 minutes away from the next hour
I am not a pm time yet, but I shall be one in the next two hours.
My hour is one away from a multiple of 3
What time am I? ( 10.42 am )
9:25
a.m.
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10:42
a.m.
7:32
a.m.
5:17 p.m.
I am between 13:30 and 19:30
I am less than 15 minutes away from being a half-past time.
I am closer to 19:00 than to 15:00
In 5 hours’ time, I shall still be a pm time.
What time am I? ( answer: 5:17pm )
4. Reinforcing the Concept and Skill
Ask the pupils to do exercises under Get Moving on page ….. LM Grade 5
For further practice, ask the pupils to work on exercises under Keep Moving on
page..LM Grade 5.
5. Summarizing the Lesson
Let the pupils to generalize
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If the two digit to left is less than 12 time shows the morning hours that is before 12 o’
clock noon or am. But if the digits are more than that, means the time is the 12 noon or
pm.
While converting 12 hours time to 24 hours time, add 12 to the hours and keep the
minutes same
While converting 24 hours time to 12 hours time, subtract 12 hours from the hours and
keep the minute same.
6.
Applying to New and other Situations
Converting 24 hours clock times
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C. Assessment
A.
Ask pupils to answer exercise under Apply your Skills on page…of LM Grade 5
B.
Read and answer the Time Riddles
Challenge A.
 I am between 3 o’ clock and quarter to 11.
 My hour will not change in the next 20 minutes
 My hour is a multiple of 3
 I am less than 15 minutes away from a half- past time.
What time am I? _______ ( Answer: 3:28 )
Challenge B
 In less than half an hour I shall reach the next o’clock time.
 I am more than 10 minutes away from a half-past time.
 I am closer to 5 o’clock than to 11 o’clock.
 My hour will not change in the next 5 minutes.
What time am I? ________ ( Answer 6:48 )
D.
Home Activity
Remediation
Change the following time from 24 hour system.
1. 0715
2. 0400
3. 1232
4. 1645
5. 1315
Change the following times to 24 hour system.
6. 3:45 a.m. =
7. 12:00 midnight =
8. 11:20 a.m. =
9. 4:23 a.m. =
10. 8:00 p.m. =
E.
Enrichment
The times below are in a 12 hour clock format. Convert and write these times using the 24
hour clock conversation ( the first one is done for you )
3:00 p.m. – 15:00
6:45 p.m. _____
5:15 p.m. - ______
1:25 p.m. ______
4:15 p.m. - _____
5:15 p.m. _____
8:05 p.m. - ______
7:35 pm- ______