Math 2 Lesson: Hours, minutes

### 1.1. Knowledge to remember

I understand the relationship between hours and minutes; how to tell the time when the minute hand points to 12, 3 or 6.

### 1.2. Math forms

**Form 1: See the given clock and then read the time.**

– Identify the hour and minute hands

– When the minute hand points to 12, I read the whole time;

– The minute hand points to the number 3, then I read the hours and 15 minutes;

– The minute hand points to the number 6, then I read the hours and 30 minutes or “half”.

**Form 2: Add and subtract time units.**

When adding or subtracting two numbers with the same unit of measure, add (subtract) the numbers and keep the unit of measure in the result.

**Form 3: Calculate the elapsed time.**

If you want to find the time interval between two quantities with the same unit of time, you subtract the small number from the larger number and keep the unit of measurement in the result.

### 1.3. Solving Textbook Exercises page 125

**Lesson 1**

What time the clock shows:

__Solution method__

Locate where the minute and hour hands are pointing, and then read the hours respectively.

__Solution guide__

Clock A shows 7:15 a.m.

Clock B shows 2:30pm (or 2:30pm).

Clock C shows 11:30 a.m. (or 11:30 a.m.).

Clock D shows 3 o’clock.

**Lesson 2**

What clock does each picture correspond to?

__Solution method__

Read the information on each picture and then find the corresponding clock.

__Solution guide__

Painting Mai wakes up at 6 o’clock, it corresponds to clock C.

Painting of Mai having breakfast at 6:15, it corresponds to the clock D.

Painting Mai arrives at school at 7:15, it corresponds to clock B.

Painting: Mai comes home from school at 11:30, it corresponds to clock A.

**lesson 3**

Calculation (according to the form):

**a) 1 hour + 2 hours = 3 hours b) 5 hours – 2 hours = 3 hours**

5 hours + 2 hours = 9 hours – 3 hours =

4 hours + 6 hours = 12 hours – 8 hours =

8 hours + 7 hours = 16 hours – 10 hours =

__Solution method__

Calculate with numbers and then write “hours” after the result.

__Solution guide__

a) 5 hours + 2 hours = 7 hours b) 9 hours – 3 hours = 6 hours

4 hours + 6 hours = 10 hours 12 hours – 8 hours = 4 hours

8 hours + 7 hours = 15 hours 16 hours – 10 hours = 6 hours

### 1.4. Solving Textbook Exercises page 126

**Lesson 1**

What time is the clock?

__Solution method__

Locate the hour and minute hands and then read the appropriate time.

__Solution guide__

Clock A shows 4 hours 15 minutes.

Clock B shows 1 hour 30 minutes.

Clock C shows 9:15.

Clock D shows 8:30 a.m.

**Lesson 2**

Which clock does each of the following sentences correspond to?

a) An enters school at 13:30.

b) An goes out to play at 15:00.

c) An goes back to school at 15:15.

d) An finishes school at 16:30.

e) An watered vegetables at 5:30 pm.

g) An eats dinner at 7 pm.

__Solution method__

Read the information in the given sentences and match it with the corresponding clock.

__Solution guide__

a) An enters school at 13:30, corresponding to clock A.

b) An goes out to play at 15 o’clock with clock D.

c) An goes back to school at 15:15 according to clock B.

d) An finishes school at 16:30 pm with clock E.

e) An watered vegetables at 5:30 p.m. with clock C.

g) An eats dinner at 7 pm corresponding to G clock.

**lesson 3**

Turn the hands on the watch face so that the watch shows:

2 o’clock; 1 hour 30 minutes; 6 hours 15 minutes; Half past 5.

__Solution method__

Based on the number of hours and minutes given, I turn the hands on the watch face.

+) Integer time: The hour hand points to the correct number of hours; The minute hand points to 12.

+) The hour has 15 minutes : The hour hand is just a little over the number of hours; The minute hand points to 3.

+) Hour and a half : The hour hand points between the two hours and the minute hand points to the number 6.

__Solution guide__

Turn the clockwise so that:

Clock shows 2 o’clock: Short hand at 2, long hand at 12.

The watch shows only 1:30: The short hand points between the 1st and the 2nd, the long hand indicates 6.

The clock only shows 6:15: The short hand is just a little past 6, the long hand is at 3.

The clock reads 5:30 a.m.: The short hand points between 5 and 6, and the long hand points to 6.

### 1.5. Solving Textbook Exercises page 127

**Lesson 1**

__Solution method__

Identify the hour and minute hands and then read the hours of each.

__Solution guide__

a) Nam and his friends arrive at the zoo at half past eight.

b) Nam and his friends arrive at the elephant stable at 9 o’clock.

c) Nam and his friends arrived at the tiger cage at 9:15.

d) Nam and his friends rest at 10:15.

e) Nam and his friends left at 11 o’clock.

**Lesson 2**

a) Ha arrives at school at 7 o’clock, Toan arrives at school at 7:15. Who gets to school earlier?

b) Ngoc goes to bed at 9pm, Quyen goes to bed at 9:30pm. Who goes to bed later?

__Solution method__

– People who arrive earlier have fewer hours.

– People who go to bed later have more hours.

__Solution guide__

a) Ha comes to school earlier than Toan.

b) Quyen goes to bed later than Ngoc.

**lesson 3**

Fill in the hours or minutes in the appropriate dot:

a) Every day Binh sleeps about 8…

b) Nam walks from home to school in 15…

c) I take the test in 35…

__Solution method__

Depending on the case to enter the appropriate hour or minute unit.

**Attention: **1 hour = 60 minutes.

__Solution guide__

a) Every day Binh sleeps about 8 hours.

b) Nam walks from home to school in 15 minutes.

c) You take the test in 35 minutes.

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