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Solving 7th-grade Math, Page 42, Workbook 1, Sky Horizon Creative Series provides detailed instructions for exercises 1, 2, 3... of Chapter 3: Rounding Numbers and Estimating Results in Chapter 2: Arithmetic. Students are encouraged to refer to this resource for easier and more effective practice.
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Solving 7th-grade Math, Page 42, Workbook 1, Sky Horizon Creative Series
Rounding Numbers and Estimating Results
1. Solving Exercise 1 Page 42 Mathematics Textbook Grade 7
Guidance for solving:
Step 1: Write the given numbers in decimal form, then round them.
Step 2: To round decimal numbers to a certain decimal place, follow these steps:
- Underline the decimal digit of the decimal place.
- Look at the digit immediately to the right:
+ If that digit is greater than or equal to 5, increase the underlined digit by one unit and replace all digits to the right with zeros or discard them if they are in the decimal part.
+ If that digit is less than 5, keep the underlined digit as it is and replace all digits to the right with zeros or discard them if they are in the decimal part.
Answer:
2. Solving Exercise 2 Page 42 Mathematics Textbook Grade 7
Guidance for solving:
Step 1: Write the given numbers in decimal form, then round them.
Step 2: To round decimal numbers to a certain decimal place, follow these steps:
- Underline the decimal digit of the decimal place.
- Look at the digit immediately to the right:
+ If that digit is greater than or equal to 5, increase the underlined digit by one unit and replace all digits to the right with zeros or discard them if they are in the decimal part.
+ If that digit is less than 5, keep the underlined digit as it is and replace all digits to the right with zeros or discard them if they are in the decimal part.
Answer:
3. Solving Exercise 3 Page 42 Mathematics Textbook Grade 7
Guidance for solving:
- If the accuracy level d is in the thousandths place, we usually round a to the hundredths place.
- If the accuracy level d is in the hundredths place, we usually round a to the thousandths place.
Answer:
4. Solving Exercise 4 Page 42 Mathematics Textbook Grade 7
Problem: The population of Vietnam as of January 20, 2021 is 97,800,744 people (source: danso.org/viet-nam). Round this number to the nearest million.
Guidance for solving:
To round a decimal number to a certain decimal place, follow these steps:
- Underline the decimal digit of the decimal place.
- Look at the digit immediately to the right:
+ If that digit is greater than or equal to 5, increase the underlined digit by one unit and replace all digits to the right with zeros or discard them if they are in the decimal part.
+ If that digit is less than 5, keep the underlined digit as it is and replace all digits to the right with zeros or discard them if they are in the decimal part.
Answer:
When rounding the population of Vietnam as of January 20, 2021 to the nearest million, we get: 98,000,000 people.
5. Solving Exercise 5 Page 42 Mathematics Textbook Grade 7
Problem: Calculate the total number of international tourists to Vietnam in the first 9 months of 2019, which reached 12,870,506 visitors (source: vietnamtourism.gov.vn). Round this number to the nearest hundred.
Guidance for solving:
To round a decimal number to a certain decimal place, follow these steps:
- Underline the decimal digit of the decimal place.
- Look at the digit immediately to the right:
+ If the digit is greater than or equal to 5, increase the underlined digit by one unit and replace all digits to the right with zeros or discard them if they are in the decimal part.
+ If the digit is less than 5, keep the underlined digit as it is and replace all digits to the right with zeros or discard them if they are in the decimal part.
Answer:
When rounding the total number of international tourists to Vietnam in the first 9 months of 2019 to the nearest hundred, we get: 12,870,500 people.
6. Solving Exercise 6 Page 42 Mathematics Textbook Grade 7
Problem: Given 1 inch = 2.54 cm. Calculate the diagonal length in cm of a 32-inch screen and round it to the tenths place.
Guidance for solving:
Step 1: Convert the unit from inch to cm, then round the result to the tenths place.
Step 2: To round decimal numbers to a certain decimal place, follow these steps:
- Underline the decimal digit of the decimal place.
- Look at the digit immediately to the right:
+ If that digit is greater than or equal to 5, increase the underlined digit by one unit and replace all digits to the right with zeros or discard them if they are in the decimal part.
+ If the digit is less than 5, keep the underlined digit as it is and replace all digits to the right with zeros or discard them if they are in the decimal part.
Answer:
The diagonal length of a 32-inch screen is:
32 x 2.54 = 81.28 ≈ 81.3 (cm).
7. Solving Exercise 7 Page 42 Mathematics Textbook Grade 7
Problem: An international airline stipulates that each passenger can carry two pieces of luggage without charge; each piece of luggage must not exceed 23 kg. Determine if a piece of luggage weighing 50.99 pounds after conversion to kilograms and rounded to the nearest unit exceeds the weight regulation? (Given 1 pound = 0.45359237 kg.)
Guidance for solving:
Step 1: Convert pounds to kilograms.
Step 2: Round the number.
Step 3: Compare the weight of the luggage and the prescribed weight limit.
Answer:
We hope this Mathematics solving guide for page 42 of the book 'Creative Horizon' will be helpful for you, enabling you to solve Mathematics problems effectively and easily.
Additional References:
- Solving Mathematics Grade 7 Page 45 Workbook 1 'Creative Horizon' - Exercise at the end of Chapter 2
- Solving Mathematics Grade 7 Page 49, 50 Workbook 1 'Creative Horizon' - Exercise 1: Rectangular Prism - Cube
