1.1. Knowledge to remember
c. Date, time
How to read information about the number of days, things … in a monthly calendar.
1.2. Math forms
Type 1: Read the mass of the object on the balance.
Determine where the scale’s needle is pointing and then read the weight of the object.
Type 2: View the monthly calendar and then answer the questions.
Read the information on a given monthly calendar and then answer the questions.
Form 3: Watch the time
Locate where the hour and minute hands are pointing and then read the hours respectively.
1.3. Solving Textbook Exercises page 174
a) What time is the clock?
b) In the afternoon, which two clocks show the same time?
– Locate the hour and minute hands and then read the time of the watch.
– Afternoon time is calculated by adding 12 hours to the time indicated on the clock.
a) Clock A shows 3:30.
Clock B shows 5 hours and 15 minutes.
Clock C shows 10 o’clock.
Clock D shows 8:30 a.m.
b) Connect clock A to clock E.
Connect clock B to clock D.
Connect clock C to clock G.
Small can hold \(10\ell\) fish sauce, big can hold more than small can\(5\ell\) fish sauce. How many liters of fish sauce can the big can hold?
Can baby: \(10\ell\)
Can bigger than small can: \(5\ell\)
Can to: ….\(\ell\)?
To find the answer, we take the number of liters of fish sauce can hold plus \(5\ell\).
The large can that holds the number of liters of fish sauce is:
\(10 + 5 = 15 (\ell)\)
Answer: \(15\ell\) fish sauce.
Binh has 1000 dong, you buy a stamp to send a letter for 800 dong. Ask Binh how many hundred dong left?
Yes: 1000 VND
Spent: 800 VND
Left: … copper?
To find the answer, we subtract the amount of money Binh has spent.
Binh has the remaining amount:
1000 – 800 = 200 (VND)
Answer: 200 dong.
Write mm, cm, dm or km in the appropriate dot:
a) The ballpoint pen is about 15…
b) A multi-storey house about 15…
c) The distance between Ho Chi Minh City and Can Tho is about 174…
d) The thickness of the pen box is about 15…
e) A glove about 2…
Rehearse the relationship between the length units already learned, depending on each case to use the appropriate unit.
1km = 1000m; 1dm = 10 cm = 100mm
a) The ballpoint pen is about 15 cm long.
b) A multi-storey house about 15 m high.
c) The distance between Ho Chi Minh City and Can Tho is about 174 km long.
d) The thickness of the pen box is about 15 mm.
e) A glove about 2 dm long.
1.4. Solving Textbook Exercises page 175
The following table shows the time Ha spends on some activities during the day:
Which of the above activities does Ha spend the most time on?
– Using knowledge: 1 hour = 60 minutes.
– Compare the time spent on activities and then answer the questions.
Ha spends the most time on learning activities.
Binh weighs 27 kg, Hai weighs 5 kg more than Binh. How many kilograms does Hai weigh?
Hai is heavier than Binh: 5kg
To find the solution, we take Binh’s weight plus 5kg.
Hai’s weight in kilograms is:
27 + 5 = 32 (kg)
Answer: 32 kg.
Dinh Xa and Hoa Hiep communes are 11km apart. Phuong’s house is 20km from Hiep Hoa commune (see picture). How far is Phuong’s house from Dinh Xa commune?
To find the answer, we take the distance from Phuong’s house to Hiep Hoa commune minus the distance from Dinh Xa commune to Hiep Hoa commune.
Phuong’s house is kilometers from Dinh Xa commune.
20 – 11 = 9 (km)
A pumping station must pump water in 6 hours, starting at 9 o’clock. What time will the pump be finished?
Find the solution by adding the time at the start of the water pump plus 6.
The pumping station is finished pumping at:
9 + 6 = 15 (hours)
3pm = 3pm
Answer: 3 pm.