To round two- and three-digit whole numbers to the nearest 10 or 100, follow these steps:

1. Identify the place value you are rounding to. If you are rounding to the nearest 10, look at the ones digit. If you are rounding to the nearest 100, look at the tens digit.

2. Look at the digit to the right of the place value you are rounding to. If this digit is 5 or greater, round up. If it is 4 or less, round down.

3. Change all the digits to the right of the place value you are rounding to to zero.

4. If you rounded up, increase the digit in the place value you are rounding to by 1.

Here are some examples:

Example 1: Round 47 to the nearest 10. - The ones digit is 7. - The digit to the right of the ones digit is 0. - Since 0 is less than 5, we round down. - Change all the digits to the right of the ones digit to zero. - The rounded number is 40.

Example 2: Round 85 to the nearest 10. - The ones digit is 5. - The digit to the right of the ones digit is 0. - Since 0 is less than 5, we round down. - Change all the digits to the right of the ones digit to zero. - The rounded number is 80.

Example 3: Round 347 to the nearest 100. - The tens digit is 4. - The digit to the right of the tens digit is 7. - Since 7 is greater than 5, we round up. - Change all the digits to the right of the tens digit to zero. - Increase the tens digit by 1, so it becomes 5. - The rounded number is 400.

Remember to always look at the digit to the right of the place value you are rounding to when deciding whether to round up or down.