In this video we discuss how to round off whole numbers or numbers that do not have decimal numbers. We go through a few examples and explain when to round up and when to round down.
Transcript/notes
When rounding whole numbers, there are 3 basic steps.
Number 1 is to locate the place of the digit to be rounded and underline it. Number 2 is to identify the digit to its right, and if that digit is 5 or more, increase the value of the digit being rounded by 1, if that digit is 4 or less, do not change the value of the digit being rounded. And number 3 is to change all of the digits to the right of the underlined digit to zeros.
As an example here are 3 numbers and what they need to be rounded to. For the first number, 429, to the nearest ten, so 2 is in the tens column, so underline it. The first digit to the right of the underlined digit is 9, which is greater than 5, so we need to increase the underlined digit by 1, so 2 becomes 3. And we need to change all of the digits to the right of the underlined digit to zero, so 9 becomes zero, and our final answer is 430.
The next number, 624,499 needs to be rounded to the nearest ten thousand. 2 is the digit in the ten thousands column, so it gets underlined. The first digit to the right of the underlined digit is 4, which is not 5 or more, so the value of the underlined digit does not change. And next we need to change all of the values of the digits to the right of the underlined digit to zeros, and our final answer is 620,000.
Here are a few more examples written out, and the key to rounding really is identifying the place of the digit being rounded and then checking if the digit to its right is 5 or greater.
Timestamps
0:00 3 steps to rounding off whole numbers
0:24 Example 1 of rounding off a whole number
0:52 Example 2 of rounding off a whole number
1:20 More examples of rounding off whole numbers