Rounding Whole Numbers
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Rounding whole numbers involves finding compatible numbers that are close in value to the original number to make arithmetic computations easier. To round, we determine which compatible number (multiples of 10, 100, 1000, etc.) the given number is closer to on a number line. If the digit to the right of the place value we are rounding to is 5 or higher, we round up. If it is 4 or lower, we round down. Examples are provided to illustrate rounding to the nearest ten, hundred, and thousand.
Rounding Whole Numbers
- 1. Rounding Whole NumbersSteven DiazMath 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 IdeaTo 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 placeYour compatible numbers are multiples of 10. Example: round 63 to the nearest ten.63Observe: 63 is closer to 60 to than 70. So, 63 is rounded to 60.
- 5. Round to nearest hundreds placeYour compatible numbers are multiples of 100. Example: round 374 to the nearest hundred.374Observe: 374 is closer to 400 than to 300. So, 374 is rounded to 400.
- 6. Round to nearest thousands placeYour compatible numbers are multiples of 1000. Example: round 1499 to the nearest hundred.1499Observe: 1499 is closer to 1000 than to 2000. So, 1499 is rounded to 1000.
- 7. Rounding Without VisualsScenario 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 4Compatible 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 VisualsScenario 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 9Compatible 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.