Rounding to the Nearest Ten and Hundred

Introduction

Rounding is a method used to simplify numbers while maintaining their value to a certain degree. In this lesson, we will focus on rounding numbers to the nearest ten and hundred.

Rounding to the Nearest Ten

To round a number to the nearest ten:

1. Identify the digit in the tens place.
2. Look at the digit in the ones place.
   • If it is 5 or greater, add 1 to the tens digit.
   • If it is less than 5, keep the tens digit the same.
3. Replace the ones digit with 0.

Example:

Round 47 to the nearest ten:

• The tens digit is 4, and the ones digit is 7.
• Since 7 is greater than 5, we add 1 to 4, which gives us 5.
• Therefore, 47 rounded to the nearest ten is:

$$50$$

Rounding to the Nearest Hundred

To round a number to the nearest hundred:

1. Identify the digit in the hundreds place.
2. Look at the digit in the tens place.
   • If it is 5 or greater, add 1 to the hundreds digit.
   • If it is less than 5, keep the hundreds digit the same.
3. Replace the tens and ones digits with 0.

Example:

Round 284 to the nearest hundred:

• The hundreds digit is 2, and the tens digit is 8.
• Since 8 is greater than 5, we add 1 to 2, resulting in 3.
• Therefore, 284 rounded to the nearest hundred is:

$$300$$

Key Questions

• What is the rule for rounding up?
• How does the digit in the ones or tens place affect rounding?