Buzz
Refer to more excellent solving materials:
- Full set of Solving Mathematics Grade 7 Creative Horizon book
- Solving Grade 7 Mathematics page 16 Volume 1 Cánh Diều book - Exercise 2. Adding, subtracting, multiplying, dividing rational numbers
- Solving Grade 7 Mathematics page 13 Volume 1 Kết Nối Tri Thức book - Exercise 2: Adding, subtracting, multiplying, dividing rational numbers
Solve exercises on pages 15, 16, 17 Mathematics Grade 7 Workbook Volume 1, the Creative Horizon book:
Operations with Rational Numbers
1. Solve Exercise 1 Page 15 Mathematics Grade 7 Workbook
Solution:
Convert numbers to fractions.
Perform addition, subtraction, multiplication, division with rational numbers.
Answer:
2. Solve Exercise 2 Page 15 Mathematics Grade 7 Workbook
Problem: Calculate:
Solution:
- Convert decimal numbers to fractions (if any).
- Perform calculations following the order of multiplication, division first, addition and subtraction later.
Answer:
3. Solve Exercise 3 Page 16 Mathematics Grade 7 Workbook
Solution: Perform the calculation then compare.
Answer:
4. Solve Exercise 4 Page 16 Mathematics Grade 7 Workbook
Problem: Calculate:
Guide to solve exercises on pages 15, 16, 17 Mathematics Grade 7 Workbook:
Apply the distributive property of multiplication over addition: a.c + b.c = (a + b).c.
Apply the commutative property of addition.
Answer:
5. Solve Exercise 5 Page 16 Mathematics Grade 7 Workbook
Problem: Find x, given:
Solution:
+ To find the unknown factor, we divide the product by the remaining factor.
+ To find the divisor, we divide the dividend by the quotient.
Answer:
6. Solve Exercise 6 Page 16 Mathematics Grade 7 Workbook
Instructions: Length of the new water pipe = Sum of the lengths of the two water pipes - length of the common connecting part.
Answer:
The length of the new water pipe is:
So the length of the new water pipe is: 2.07 m.
7. Solve Exercise 7 Page 16 Mathematics Grade 7 Workbook
Problem: A factory completed 4/15 of the monthly plan in the first week, 7/30 of the plan in the second week, and 3/10 of the plan in the third week. How much of the plan does the factory need to complete in the last week to meet the monthly plan?
Solution:
+ Calculate the total parts of work completed after three weeks by the factory.
+ The amount of work the factory needs to complete in the last week = 1 - the total parts of work completed after three weeks by the factory.
Answer:
8. Solve Exercise 8 Page 16 Mathematics Grade 7 Workbook
Problem: In June, the listed price of a 42-inch TV at an electronics supermarket was 8,000,000 dong. By September, the supermarket reduced the price by 5% for each TV. In October, the supermarket reduced the price again, and now the price of a 42-inch TV is only 6,840,000 dong. How much percent did the supermarket reduce the price of a TV compared to September?
Solution:
- Calculate the price of the TV in September.
- Calculate the amount of money the TV was discounted in October.
- Calculate the percentage of the price after the supermarket reduced the price in October compared to September.
Answer:
In the month, the TV price is: 100% - 5% = 95% compared to the listed price.
The price of the TV in September is:
8,000,000 x 95 : 100 = 7,600,000 (dong)
The amount the supermarket discounted in October is:
7,600,000 - 6,840,000 = 760,000 (dong)
In October, the supermarket reduced the price by percentage compared to September is:
760,000 : 7,600,000.100 = 10%
So in October, the supermarket reduced the price by 10% compared to September.
9. Solve Exercise 9 Page 16 Mathematics Grade 7 Workbook
Problem: A bookstore has a promotion as follows: Members will get a 10% discount on the total amount of the bill. Lan has a membership card and she buys 3 books, each priced at 120,000 dong. Lan gives the cashier 350,000 dong. How much money will Lan get back?
Solution:
- Calculate the original price of 3 books.
- Calculate the price of 3 books after the discount.
- Calculate the amount of money Lan gets back when she gives the cashier 350,000 dong.
Answer:
The original price of 3 books is:
3 x 120,000 = 360,000 (dong)
After being discounted by 10%, the price of 3 books equals 90% of the original price.
The price of 3 books after being discounted is:
360,000 x 90 : 100 = 324,000 (dong)
Lan gets back the amount of money:
350,000 - 324,000 = 26,000 (dong)
The diameter of Venus is 6/25 of the diameter of Neptune. The diameter of Neptune is 5/14 of the diameter of Mercury.
a) The diameter of Venus is 25/70 parts of the diameter of Mercury. b) Given that the diameter of Mercury is approximately 140,000 km, calculate the diameter of Venus.
The diameter of Venus is related to the diameter of Neptune and Mercury in the following way: If A is x times B, and B is y times C, then A is x.y times C.
In the troposphere, the temperature decreases with altitude. For every increase of 100 m in altitude, the air temperature decreases by approximately 0.6°C.
Next up:
- Solving Math for 7th Grade, pages 20 and 21, Volume 1 of the book 'Horizon of Creative Thinking' - Exercise 3: Exponents of a Rational Number
- Solving Math for 7th Grade, pages 24 and 25, Volume 1 of the book 'Horizon of Creative Thinking' - Exercise 4: Parentheses and Transposition Rule
