A simple Power Point presentation explaining the basic idea of rounding whole numbers.

1. Rounding Whole Numbers Steven Diaz Math Instructor

2. What is rounding? To find compatible numbers with similar values as the original numbers, so arithmetic computations are easier to perform (i.e. estimate).

3. Basic Idea To round a whole number, we look how close is the number from two compatible numbers of our interest on a number line.

4. Round to nearest tens’ place Your compatible numbers are multiples of 10. Example: round 63 to the nearest ten. 63 Observe: 63 is closer to 60 to than 70. So, 63 is rounded to 60.

5. Round to nearest hundreds’ place Your compatible numbers are multiples of 100. Example: round 374 to the nearest hundred. 374 Observe: 374 is closer to 400 than to 300. So, 374 is rounded to 400.

6. Round to nearest thousands’ place Your compatible numbers are multiples of 1000. Example: round 1499 to the nearest hundred. 1499 Observe: 1499 is closer to 1000 than to 2000. So, 1499 is rounded to 1000.

7. Rounding Without Visuals Scenario 1: When a number is at least halfway the distance between two compatible numbers, the digit to the right of the place value that we want to round in the numeral is 5 or higher. Example: Round 374 to the nearest hundred. 3 7 4 Compatible numbers are multiples of 100. 374 is between 300 and 400. Observe: The digit 3 is in the hundreds’ place and the digit to its right is 7, so it means that 374 is closer to 400 than to 300. 374 is rounded to 400.

8. Rounding Without Visuals Scenario 2: When a number is less than halfway the distance between two compatible numbers, the digit to the right of the place value that we want to round in the numeral is 4 or lower. Example: Round 1499 to the nearest thousand. 1 4 9 9 Compatible numbers are multiples of 1000. 1499 is between 1000 and 2000. Observe: The digit 1 is in the thousands’ place and the digit to its right is 4, so it means that 1499 is closer to 1000 than to 2000. 1499 is rounded to 1000.