Rounding Whole Numbers
Concept
Rounding Numbers means adjusting the digits of a number in such a way that it gives an approximate value. This value is an easier representation of the given number.
Rounding a number means the process of making a number simpler such that its value remains close to what it was. The result obtained after rounding off a number is less accurate, but easier to use. While rounding a number, we consider the place value of digits in a number.
Rules
Rules for Rounding Numbers
There are some basic rules that need to be followed for rounding numbers.
When rounding a number, you first need to ask: what are you rounding it to? Numbers can be rounded to the nearest ten, the nearest hundred, the nearest thousand, and so on.
We first need to know what our rounding digit is. This digit is the one that will ultimately be affected.
After this, we need to check the digit to the right of this place which will decide the fate of the rounding digit.
If the number you are rounding is followed by 0, 1, 2, 3, or 4, we do not change the rounding digit. However, all the digits to the right of the rounding digit are changed to 0.
If the number you are rounding is followed by 5, 6, 7, 8, or 9, we increase the rounding digit by 1, and all the digits to the right of the rounding digit are changed to 0.
Rounding Numbers to the Nearest Ten
Rounding numbers to the nearest ten means we need to check the digit to the right of the tens place, that is the ones place. For example, when we round the number 3186 to the nearest ten, it becomes 3190.
Rounding Numbers to the Nearest Hundred
Rounding numbers to the nearest hundred means we need to check the digit to the right of the hundreds place, that is, the tens place. For example, when 8453 is rounded to the nearest hundred, it becomes 8500.
Example
Round 33,725 to the nearest ten thousand.
Solution
Consider the place value. The number is being rounded to ten thousand. Either round the number up to 40,000 or down to 30,000. If the digit in the thousands place is less than 5, then round the number down to 30,000. Otherwise, round the number up to 40,000.
The answer is 30,000
Practice Rounding Whole Numbers
Practice Problem 1
Round 68 to the nearest ten.
Type the nearest ten.
Practice Problem 2
Round 368 to the nearest hundred.
Type the nearest hundred.
Practice Problem 3
Round 234 to the:
Practice Problem 4
Round 2,517 to the nearest thousand.
Place value – is the value of each digit in a number.
Rounding a number means the process of making a number simpler such that its value remains close to what it was.