Tuesday, October 25, 2011

ROUNDING

What is rounding?

Rounding means reducing the digits in a number while trying to keep its value similar. 

For example:
Number 62 is between 60 and 70, but when it rounded to the nearest ten is 60, because 62 is closer to 60 than to 70.

How to round numbers?

  1. Decide the place value (the last digit to keep). Exp: tens, hundreds, thousands etc
  2. Leave it the same if the next digit is less than 5. (Rounding down)
  3. Increase it by 1 if the next digit is 5 or more. (Rounding up)
  4. Lastly, replace the removed digit with “0”.

Example: Round 34 to the nearest tens.

  1. We want to keep the “3” as it is in the tens position.
  2. The next digit is “4” which is less than 5, so no change is needed to “3”
  3. As a result, the answer is “30”, 34 gets rounded down.

Example: Round 48 to the nearest tens.

  1. We want to keep the “4”.
  2. The next digit is “8” which is 5 or more, so increase the “4” by 1 to “5”.
  3. As a result, the answer is “50”, 48 gets rounded up.

So, when the first digit removed is 5 or more, increase the last digit remaining by 1.

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