Solving math problems in grade 5, pages 46, 47, 48 of VBT Workbook, Self-assessment, Exercise 121

The solution for solving math problems in grade 5, pages 46, 47, 48 of VBT Workbook, Self-assessment, Exercise 121, includes guidance and answers for exercises 1, 2, 3, 4 in part 1 and exercises 1, 2 in part 2 according to the curriculum. Students can refer to it to do exercises, reinforce knowledge, and learn how to apply it to exercises.

Part 1 - 1. Solve Exercise 1 - Math Workbook Grade 5 Volume 2 Page 46

Problem Statement:

What is 2% of 1000kg?

A. 10kg

B. 20kg

C. 22kg

D. 100kg

Solution Method

To find 2% of 1000kg, divide 1000 by 100 and then multiply by 2, or multiply 100 by 2 and then divide by 100.

Correct Answer

2% of 1000kg is:

1000 : 100 x 2 = 20 (kg)

Choose B.

Part 1 - 2. Solve Exercise 2 - Math Workbook Grade 5 Volume 2 Page 46

Problem Statement:

Which figure below has shaded 37.5% area?

Solution Method

Write the fraction indicating the shaded portion of each figure, then write those fractions as percentages.

Answer

*) Figure A

Area of the shaded portion occupies

1 : 3 = 0.33 = 33%

*) Figure B

The shaded area occupies

1 : 4 = 0.25 = 25%

*) Figure C

Shaded area occupies

2 : 4 = 0.5 = 50%

*) Figure D

Shaded area occupies

3 : 8 = 0.385 = 38.5%

So, Figure D has the shaded area occupying 38.5%.

There are 50 participants in a group gymnastics performance. The chart below indicates the percentage ratio of young men, young women, and teenagers participating in the group gymnastics performance. How many young women participated in the group gymnastics performance?

A. 50

B. 200

C. 250

D. 300

Observing the chart, we see that 40% of the participants in the group gymnastics performance are young women.

To find 40% of 500 people, divide 500 by 100 and then multiply by 40, or multiply 500 by 40 and then divide by 100.

Observing the chart, we see that 40% of the participants in the group gymnastics performance are young women.

The number of young women participating in the group gymnastics performance is:

200 (people)

Choose option B.

Given rectangle EGHK with a length of 12cm and a width of 9cm. Point M is the midpoint of segment KH.

The area of the shaded part of rectangle EGHK is:

A. 48cm²

B. 54cm²

C. 64cm²

D. 108cm²

- Area of shaded part = area of triangle KEM + area of triangle HMG.

- Area of right triangle = product of the lengths of the two sides of the right angle : 2.

We have EGHK as a rectangle so

EG = KH = 12cm ; EK = GH = 9cm.

Point M is the midpoint of segment KH so

KM = MH = KH : 2 = 12 : 2 = 6cm.

The area of triangle KEM is:

9 ⨯ 6 : 2 = 27 (cm² )

The area of triangle HMG is:

9 ⨯ 6 : 2 = 27 (cm²)

The area of the shaded part is:

27 + 27 = 54 (cm²)

Choose B.

Write the name of each figure below in the blank:

Observe the diagram to determine the name of each figure.

Task: Determine the required additional liters of water to achieve 95% capacity in a rectangular prism aquarium with internal dimensions of 25cm, 40cm, 50cm, where 1/4 of the volume is currently filled.

Solution Approach

- Convert dimensions to cubic meters.

- Proceed with the following method:

Calculate the aquarium volume = length x width x height.

Calculate the volume of water currently in the aquarium = aquarium volume x 1.414.

Find the volume of water in the aquarium after adding more = volume : 100 x 95.

Determine the volume of water to be added.

Answer

Convert 25cm = 2.5dm

40cm = 4dm

50cm = 5dm

The volume of the aquarium is:

2.5 ⨯ 4 ⨯ 5 = 50 (dm³)

The current water volume in the aquarium is:

50 x 1/4 = 12.5 (dm³)

95% of the water volume in the tank is:

(50x95) : 100 = 47.5 (dm³)

The number of liters of water needed to be added to the tank is:

47.5 - 12.5 = 35 (dm³) = 35l

Answer: 35 liters

You are viewing the instructions for solving math problems in Grade 5, pages 46, 47, 48 of VBT Exercise Book 2 Self-test lesson 121. You can review the instructions for solving math problems in Grade 5, page 45 of VBT Exercise Book 2 Consolidated practice or preview the instructions for solving math problems in Grade 5, pages 49, 50 of VBT Exercise Book 2 Time measurement unit table to understand more about the lesson.

Wishing you success in learning mathematics.