Round each of the following numbers to the nearest hundred. (i) 492 (ii) 647 (iii) 685 (iv) 421 (v) 5728
The Correct Answer and Explanation is:
To round each number to the nearest hundred, you need to follow a simple rule:
- If the tens digit is 5 or greater, round up to the next hundred.
- If the tens digit is less than 5, round down (or simply keep the number as is at the lower hundred).
Step-by-Step Rounding:
(i) 492:
- The tens digit is 9, which is greater than 5.
- So, we round up to the nearest hundred, which is 500.
(ii) 647:
- The tens digit is 4, which is less than 5.
- So, we round down to the nearest hundred, which is 600.
(iii) 685:
- The tens digit is 8, which is greater than 5.
- So, we round up to the nearest hundred, which is 700.
(iv) 421:
- The tens digit is 2, which is less than 5.
- So, we round down to the nearest hundred, which is 400.
(v) 5728:
- The tens digit is 2, which is less than 5.
- So, we round down to the nearest hundred, which is 5700.
Explanation:
Rounding numbers is a technique used to simplify numbers while maintaining their approximate value. When rounding to the nearest hundred, you focus on the tens digit (the second number from the right) because it tells you whether the number is closer to the lower hundred or the higher one.
- If the tens digit is 5 or greater, you round up.
- If the tens digit is less than 5, you round down.
This process is a helpful way to quickly estimate values without dealing with exact figures, especially in everyday scenarios like estimating costs, distances, or quantities.
Final Rounded Answers:
- (i) 492 → 500
- (ii) 647 → 600
- (iii) 685 → 700
- (iv) 421 → 400
- (v) 5728 → 5700
