Hướng dẫn học toán lớp 4 giây thế kỉ đơn giản, dễ hiểu nhất

Studying 4 -second mathematics in the century is one of the basic knowledge, not only applied in mathematics but also related to practical time factors. So, to help children learn well about this knowledge, Mầm non Cát Linh will summarize good teaching tips and exercises for them to practice effectively.

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What is 4 -second class math?

Seconds of the century are essentially time measurement of time. In there:

• Seconds: The unit measuring time is small, ie 1 part of 60 will be 1 minute.
• The century: The unit measuring time is large, up to hundreds of years. Many times larger than the second unit.

For example:

60 seconds = 1 minute

1 century = 100 years

5 centuries = 500 years

100 years = 1 century

9 centuries = 900 years

The ways to change units of the century in Grade 4 Mathematics

In essence, the conversion of units of the century is also quite simple. Specifically:

1 hour = 60 minutes and 1 minute = 60 seconds 1 century = 100 years From year 1 to 100 is the first century (first century) From 101 to 200 is the second century (second century) …. From 2001 to 2100 is the twenty -one century (21st century)

* Note: The century is usually written in Roman numerals

Summary of 4 -second math exercises with detailed solutions

To help them easily conquer this math, here are some math exercises in the 4th grade mathematics with detailed instructions:

Solving exercises in the 4th grade math century, page 25 textbooks

Solution method: The children apply the rules to change units and the above centuries to solve the exercise.

Grade 4 math exercises page 25 Lesson 1:

Write the appropriate number in the dot:

a) 1 minute = … seconds

60 seconds = … minutes

2 minutes = … seconds

7 minutes = … seconds

1/3 minutes = … seconds

1 minute 8 seconds = … seconds

b) 1 century = … year

100 years = ….. century

5 centuries = … year

9 centuries = …. year

1/2 century = … year

1/5 century = …. year

Answer:

a) 1 minute = 60 seconds

60 seconds = 1 minute

2 minutes = 120 seconds

7 minutes = 420 seconds

1/3 minutes = 20 seconds

1 minute 8 seconds = 68 seconds

b) 1 century = 100 years

100 years = 1 century

5 centuries = 500 years

9 centuries = 900 years

1/2 century = 50 years

1/5 century = 20 years

Grade 4 math exercises on page 25 Lesson 2:

a) Uncle Ho was born in 1890. What century did Uncle Ho be born in the century?

Uncle Ho went to find a way to save the country in 1911. Which century was that year?

b) What century was the August Revolution in 1945. Which century was that year?

c) Mrs. Trieu led the uprising against Dong Ngo army in 248. In which century was that century?

……………

– From 1901 to 2000 was the twenty century (twentieth century).

– From 2001 to 2100 was the twenty -one century (21st century).

Answer:

a) Uncle Ho was born in 1890. Uncle Ho was born in the nineteenth century (nineteenth century)

Uncle Ho went to find a way to save the country in 1911. That year was in the twentieth century (twentieth century)

b) The August Revolution was successful in 1945. That year was in the twentieth century (twentieth century).

c) Mrs. Trieu leader the uprising against the Dong Ngo army in 248. That year in the third century (III century)

Grade 4 math exercises on page 25 Lesson 3:

a) Ly Thai To moved the capital to Thang Long in 1010. Which century in that year? How many years is it?

b) Ngo Quyen defeated Nam Han troops on the Bach Dang River in 938. Which century in that year? How many years is it?

Answer:

a) Ly Thai To moved the capital to Thang Long in 1010. That year was in the 11th century.

Up to now (2021) has been the number of years:

2021 – 1010 = 1011 (year)

b) Ngo Quyen defeated Nam Han troops on the Bach Dang River in 938. That year was in the 10th century.

Up to now (2021) has been the number of years:

2021 – 938 = 1083 (year).

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Solving exercises in the 4th grade math century, page 26 sgk

Solution: They need to review the knowledge of time measurement units such as day, month, year, hour, minute, and seconds to solve the exact exercise.

Grade 4 math exercises on page 26 Lesson 1:

a) Name the months: 30 days; 31 days; 28 (or 29) day.

b) Indicate: The leap year is the year that February has 29 days

In the leap years, February is only 28 days.

Question: How many days? How many days without leaps?

Answer:

a) The months of 30 days are: April; June; September; November.

The months of 31 days are: January; March; May; July; August; October; December.

The month has 28 (or 29) days is February.

b) The leap year has 266 days. Non -leap year has 365 days.

Grade 4 math exercises on page 26 Lesson 2:

3 days = … time

4 hours = …. minutes

8 minutes = … seconds

1/3 day = … time

1/4 time = …. time

1/2 minutes = … seconds

3 hours 10 minutes = … hours

2 minutes 5 seconds = … seconds

4 minutes 20 seconds = … seconds

Answer:

3 days = 72 hours

4 hours = 240 minutes

8 minutes = 480 seconds

1/3 day = 8 seconds

1/4 hours = 6 hours

1/2 minutes = 30 seconds

3 hours 10 minutes = 190 hours

2 minutes 5 seconds = 125 seconds

4 minutes 20 seconds = 260 seconds

Grade 4 math exercises on page 26 Lesson 3:

a) Quang Trung Dai broke the Qing army in 1789. Which century was that year?

b) The 600th anniversary of Nguyen Trai’s birth was held in 1980. What year was Nguyen Trai born? Which century in that year?

Answer:

a) Quang Trung Dai broke the Qing army in 1789. That year was in the eighteenth century (eighteenth century).

b) The 600th anniversary of Nguyen Trai’s birth was held in 1980. Thus, Nguyen Trai was born: 1980 – 600 = 1380.

That year in the fourteenth century (XIV century).

Grade 4 math exercises on page 26 Lesson 4:

In the 600m competition, Nam runs for 1/4 minute, Binh runs for 1/5 minutes. Ask who runs faster and faster than seconds?

Answer:

We have:

1/4 minutes = 15 seconds

1/5 minutes = 12 seconds

Because 12 seconds <15 seconds

So Binh runs faster than Nam. And faster than the second number: 15 – 12 = 3 seconds Answer: 3 seconds

Grade 4 math exercises on page 26 Lesson 5:

Circle the word before the correct answer:

a) Clock only

A. 9 hours 8 minutes

B. 8 hours 40 minutes

C. 8 hours 45 minutes

D. 9 hours 40 minutes

b) 5kg 8g =?

A. 58g

B. 508g

C. 5008g

D. 580g

Answer:

a) The clock is only 8 hours 40 minutes.

Circle B.

b) We have: 1kg = 1000g so 5kg = 5000g.

Therefore: 5kg 8g = 5kg + 8g = 5000g + 8g = 5008g.

So: 5kg 8g = 5008g.

Circle C.

Some math exercises in the second century expanded Grade 4 mathematics for them to practice themselves

In addition to the exercises in the 4th grade Mathematics textbook, here are some expanded exercises about the century for your reference and self -training effectively:

Lesson 1. Fill in the dot:

a) 1/4 hours = … minutes

b) 1/5 hours = … minutes

c) 2 hours 10 minutes = … minutes

d) 1 hour 23 minutes =…. minute.

Lesson 2.

a) What is 1/3 of 4 minutes?

b) What is 1/4 of 3 minutes?

c) How many seconds of 1/5 of 2 minutes?

Lesson 3.

a) 62 seconds = … minutes … seconds

b) 75 seconds = … minutes … seconds

c) 130 seconds = … minutes … seconds

d) 123 seconds = … minutes … seconds

Lesson 4. Write the Roman number in the dot:

a) In 91 of the century …

b) In 1456 in the century ….

c) 547 in the century …

d) 1901 in the century …

Lesson 5. Four classes A, B, C, D, in turn, have 34 students, 31 friends, 36 friends, 39 friends. Ask how many of you each class?

Lesson 6. Three classes donate notebooks. Class 4A contributed 40 notebooks, class 4B contributed more than 4A class is 10 volumes but less than 4C class is 4 books. Ask how many notebooks on average each class?

Lesson 7. There are 6 cars carrying rice, including 2 cars each carrying 24 quintals of rice, the remaining vehicles each carrying 18 quintals of rice. Ask how many tons of tons of rice each car?

Lesson 8. Find the average number of tens of numbers from 10 to 90

Lesson 9. The average of two numbers is 16.

Lesson 10: In the 100m swimming contest, Ha swim all 1/5 minutes and Lan swim all 1/6 minutes. Ask in the two of you, who swim faster and how many seconds faster?

Lesson 11: Fill in the appropriate number in the dot:

a) The 15th century started from the year … to the end of the year … ..

b) Mr. La Font-Ten died in 1695. That year was in the century ……

c) The victory of Dien Bien Phu in 1954. That year belonged to the century ……….

The secret to helping children to learn math 4 seconds in the century effectively

To help children easily learn, absorb and apply knowledge of the 4th grade math century, here are some effective secrets:

• Mastering theory: To solve exercises or practical applications effectively, requires children to master the theory like what is second, what is the century? How to change measurement units … If the baby forgets or does not understand, parents should support, guide and consolidate their children’s knowledge promptly.

• Application of mathematics with practice: With the unit, the century, in practice there are many such as watching watches, viewing historical programs … so that it helps children easily visualize, memorize and acquire knowledge more effectively.

• Organizing mathematical games: To create excitement for children when learning math, parents can think of games related to viewing, calculating time … combined with that, there should be more gifts to encourage and encourage if their children play to win to be more spiritual and play.

• Practice throughout: In order to avoid the child learning first, parents should encourage and ask their children to practice more through homework on textbooks, exercises, learn more on the internet, exam preparation …

• Building a solid mathematical platform for children with Mầm non Cát Linh Math: Integrating all modern methods such as teaching through videos, funny animations to help children less bored, teach through games, supplementary books …. It is a combination that helps children have excitement, passion and develop thinking when learning math more and Mầm non Cát Linh Math application. Parents can learn more about the following video applications, or register for free consultation support.

Conclude

Above is the sharing of 4 -second math knowledge in the century, a math theme applied throughout the curriculum to practice. Hopefully, with the above information will help parents, as well as the children have more teaching and math materials in a better way.

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