How To Round Off Decimal Numbers Explained

In this video we discuss how to round off decimal numbers. We go through several examples in detail showing when to round up and when to round down. Transcript/notes Number 1 is to locate the place of the digit to be rounded and draw a vertical line to the right of it. Number 2 is to identify the digit to the right of the vertical line, 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 drop all of the digits to the right of the digit you have rounded. As an example here are 3 numbers and what they need to be rounded to. For the first number, 4.29, rounded to the nearest tenth, so 2 is in the tenths column, so draw a vertical line to the right of it. The first digit to the right of the vertical line is 9, which is greater than 5, so we need to increase the digit in the tenths column by 1, so 2 becomes 3. And we need to drop all of the digits to the right of the rounded digit, so, our final answer is 4.3. The next number is 36.998, and we are going to round this to the nearest hundredth. For the nearest hundredth, the second 9 is in the hundredths column, so, we draw a vertical line to the right of it. The first digit to the right of the vertical line is eight, which is greater than 5, so we need to increase the digit in the hundredths column by 1, so 9 becomes ten. Which means we need to make that digit zero and carry the 1 to the next column to the left, so that digit, 9, becomes 10, and again, we need to make that digit zero and carry the 1 to the next column to the left, which is the tens column to the left of the decimal. So, the 6 in the tens column becomes 7, and our final answer is 37.00. Here are a few more examples written out, and the key to rounding decimals really is about identifying the place of the digit being rounded. Timestamps 0:00 3 steps to rounding off decimal numbers 0:26 Example rounding to the tenths column 0:53 Example rounding to the hundredths column 1:37 More examples rounding off decimal numbers