Watch the clock

### 1.1. Knowledge to remember

- It is necessary to distinguish which is the hour hand, which is the minute hand: For a watch with 2 hands, the hour hand and the minute hand, the short hand is the hour hand, and the long hand is the minute hand.
- When reading, read the hour hand first, the minute hand later.
- Want to know how many minutes the minute hand is showing, we count from the number onwards, the hand rotates through each number we get

$5$minutes (eg hand index 3 take 5 × 3 = 15 minutes)

### 1.2. Solving Textbook Exercises

**Lesson 1 page 13:** What time is the clock?

__Solution guide:__

A: Clock only

$4$hours

$5$minute

B: Clock only

$4$hours

$\mathrm{ten}$minute

C: Clock only

$4$hours

$5$minute

D: Clock only

$6$hours

$15$minute

E: Clock only

$7$hours

$30$minute

G: Clock only

$\mathrm{twelfth}$hours

$35$good minute

$\mathrm{first}$bad time

$25$minute

__Note:__

When the needle length has not exceeded the number

$6$In the forward direction, we read more hourly

When the needle length exceeds the number

$6$In the forward direction, we read the bad hours, when we read the bad hours, we calculate the number of minutes from the number

$\mathrm{twelfth}$counter-clockwise to the number of minutes hand is pointing

**Lesson 2 page 13:** Turn clockwise so that the clock shows:

a) 7 hours and 5 minutes; b) half past six; c) 11:50 am.

**Solution guide:**

- Dial the short hand to indicate the hours.
- Turn the long hand to indicate the number of minutes : Starting from 12 onwards, each number on the clock will correspond to 5 minutes.

a) Short hand index 7, long hand index 1

b) Short hand index 6, long hand index 6

c) The short hand is only close to 12, the long hand is only 10

**Lesson 3 page 13:** What time is the clock?

**Solution guide:**

- Read the hour first, read the minute later.
- Hours and minutes are separated by “:”

*Solution*

Clock A only

$5$hours

$20$minute

Clock D only

$14$hours

$5$minute

Clock B only

$9$hours

$15$minute

Watch E only

$17$hours

$30$minute

Clock C only

$\mathrm{twelfth}$hours

$35$minute

G only

$21$hours

$55$minute

**Lesson 4 page 14:** In the afternoon, which two clocks show the same time?

**Solution guide:**

- One day there

$24$time but on an analog clock there is only

$\mathrm{twelfth}$number, so the afternoon time on the analog clock will still be the same as the morning time.

- But it’s not like that on electronic watches

$\mathrm{twelfth}$At noon to noon, the electronic clocks are still running

$13$hours (corresponding to

$\mathrm{first}$pm),

$14$hours (corresponding to

$2$pm), …

- Want to know the afternoon time on the electronic clock corresponds to how many pm on the analog clock, we take the number of hours on the electronic clock –

$\mathrm{twelfth}$hour = The number of hours in the afternoon on an analog clock.

*Solution*

In the afternoon:

Clock A indicates:

hours –

$\mathrm{twelfth}$hour =

$4$hours

Clock C indicates:

$16$hour 30 minutes –

$\mathrm{twelfth}$hour =

$4$hours

$30$minute

Meter E indicates:

$13$hours

$25$minutes –

$\mathrm{twelfth}$hour =

$\mathrm{first}$hours

$25$minute

In the afternoon, the clocks showing the same time are:

+ Clock A and clock B (only the same

$4$hours)

+ C clock and G clock (only

$4$half past)

+ D clock and E clock (same indication)

$\mathrm{first}$hours

$25$minute).

**Lesson 1 page 15: **What time is the clock? (Answer according to the form)

**Solution guide:**

+ Clock B indicates

$\mathrm{first}$hours

$40$minutes or

$2$bad time

$20$minute.

+ C clock only

$8$hours

$35$minutes or

$9$bad time

$25$minute.

+ D-clock only

$5$hours

$50$minutes or

$6$bad time

$\mathrm{ten}$minute.

+ E-clock only

$8$hours

$55$minutes or

$9$bad time

$5$minute.

+ G-clock only

$\mathrm{ten}$hours

$45$minutes or

$11$bad time

$15$minute.

**Lesson 2 page 15:** Turn the hands of the clock so that the clock points

a) 3 hours 15 minutes; b) 9 hours to 10 minutes; c) 4 hours to 5 minutes.

**Solution guide:**

a) The short needle points to 3, the long needle points to 3

b) Short hand only closes to number 9, long hand reads 10

c) The short hand is only close to 4, the long hand is at 11

* Note:* In bad hours, want to know what the minute hand is counting from the number

counter-clockwise.

**Lesson 3 page 15:** What reading does each clock correspond to?

**Solution guide:**

Each meter corresponds to 1 reading.

**Lesson 4 page 16:** Look at the pictures and then answer the questions

**Solution guide:**

a) Minh’s friend wakes up at

$6$hours

$15$minute

b) Minh’s friend brushes his teeth and washes his face at

$6$hours

$30$minute

c) Minh’s friend has breakfast at

$7$bad time

$15$minute

d) Minh’s friend goes to school

$7$hours

$25$minute

e) Minh’s friend started going home from school at

$11$hours

g) Minh’s friend comes home at

$11$hours

$20$minute

.

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