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Guidelines for solving exercise page 19 Math 5 including solving methods
1. Solve problem 1 page 19 Math 5 textbook
Problem:
Buying 5m of fabric costs 80,000 dong. How much does it cost to buy 7m of that fabric?
Solution method:
- Given quantity: Price of 5 meters of fabric: 80000 dong
- Quantity to find: Price of 7 meters of fabric.
- Solution method:
+ Step 1: Find the price of 1 meter of fabric by dividing the total price of 5 meters of fabric by 5
+ Step 2: Find the price of 7 meters of fabric by multiplying the price of 1 meter of fabric by 7.
Answer:
+ Summary:
5m: 80,000 dong
7m: ... dong?
+ Solution:
Buying 1m of fabric costs:
80,000 : 5 = 16,000 (dong)
Buying 7m of fabric costs:
16,000 x 7 = 112,000 (dong)
Answer: 112,000 dong
2. Solve Problem 2 Page 19 Math 5 Textbook
Problem:
A reforestation team plants an average of 1200 pine trees every 3 days. How many pine trees will the team plant in 12 days?
Solution method:
1. First solution method: Applying the unit conversion method
- Step 1: Perform division to find out what one unit of quantity 1 corresponds to in quantity 2
- Step 2: Compare the remaining quantity 1 with the corresponding value (the result just found) to see how many times more or less it is.
2. Second solution method: Applying the ratio method
- Step 1: Compare 2 values of quantity 1 to determine how many times one is greater than the other
- Step 2: The known value of the second quantity will be increased or decreased by a certain number of times as found above.
Answer:
+ Summary
3 days: 1200 pine trees
12 days: ... pine trees?
+ Solution:
Compared to 3 days, 12 days is:
12 : 3 = 4 (times)
In 12 days, the team planted:
1200 x 4 = 4800 (pine trees)
Answer: 4800 pine trees.
3. Solve Problem 3 Page 19 Math 5 Textbook
Problem:
The population of a commune is currently 4000 people.
a) With an annual increase of 1000 people resulting in an additional 21 people, calculate how many more people the commune will have after one year.
b) If the annual increase is reduced to 1000 people resulting in an additional 15 people, how many more people will the commune have after one year?
Solution method:
In this problem, you can apply the method of finding ratios to solve:
- Step 1: Perform division to find how many times 4000 people is compared to 1000 people.
- Step 2: Find the number of people increased after one year by multiplying the additional people (according to the problem) by the number of times (found in step 1)
- Step 3: Find the population (in question b) by multiplying the additional population when the annual increase is reduced by the number of times (result of step 1).
Answer:
+ Summary:
1000 people: increase by 21 people
4000 people: increase ... people?
+ Solution:
4000 people compared to 1000 people is:
4000 : 1000 = 4 (times)
After one year, the population of the commune increased by
21 x 4 = 84 (people)
Answer: 84 people
b) Summary
1000 people: increase by 15 people
4000 people increase by ... people?
After one year, the population of the commune increased by:
4000 x 15 / 1000 = 60 (people)
Answer: 60 people.
Short Guide to Solving Exercise 19 Mathematics 5 Concisely
Solve Problem 1 Page 19 Math 5 Textbook, Review and Supplement about Problem Solving
Buy 5m of fabric for 80,000 dong. How much does it cost to buy 7m of that fabric?
Summary:
5m : 80,000 dong
7m: ... dong?
Solution:
Buy 1m of fabric for 80,000 : 5 = 16,000 dong
Buy 7m of fabric for 16,000 x 7 = 112,000 dong
Answer: 112,000 dong
Solve Problem 2 Page 19 Math 5 Textbook, Review and Supplement about Problem Solving
A forest planting team can plant 1200 pine trees every 3 days on average. How many pine trees can the team plant in 12 days?
Summary:
3 days: 1200 pine trees
12 days: ... pine trees?
Solution:
12 days compared to 3 days is:
12 : 3 = 4 (times)
In 12 days, the team planted:
1200 x 4 = 4800 pine trees
Answer: 4800 pine trees
Chapter II introduces us to decimal numbers, where the concept of decimal numbers is used extensively. Let's take a look at the hints for Exercise 34, 35 Math 5 Textbook to study Math 5 well.
The population in a commune currently has 4000 people. With an annual increase of 1000 people, there are 21 more people. Calculate how many people the commune will increase by in a year.
END
Here is the full detailed solution for Exercise 19 Math 5. Prepare for the content of the Practice on pages 19, 20 of Math 5 textbook through the section of Solving exercises on pages 19, 20 of Math 5 textbook and the Review and supplement about solving math problems (continued) through the section of Solving exercises on page 21 of Math 5 textbook to study Math 5 better.
In addition to the content studied, you can prepare and study the content of the Solution for exercises on page 57 of Math 5 textbook to grasp the knowledge in the Math 5 curriculum.
In the Math 5 curriculum, the Solution for exercises on pages 61, 62 of Math 5 textbook is one of the very important contents that students need to pay attention to and enhance to improve their Math 5 solving skills.
