Thursday 9 February 2012

How to perform Estimating and Rounding Numbers

Estimating and rounding is the basic need of math. These two things are used frequently in most of the math problems. Rounding and estimating comes in various physical quantities such as money, length of time, etc. Rounding off of any number is kind of or similar to estimation.
Here we will first learn rounding of the whole numbers.  In this, first we find the place value we want that is the rounding digit and then search the immediate digit to its right. If the immediate right digit is less than 5 then without changing the rounding digit just change the remaining right digit of it to zero. If that digit is greater than or equal to 5, then we will add 1 to the rounding digit and change all the right digits to zero.
Here are some examples to show estimating and rounding
1.       367 is the given number here then for estimating and rounding it we first look at the rounding digit that is 6. Now we will take the right digit of this rounding digit 6 that is 7. Here 7 is greater than 5 so we will add 1 to the rounding digit as 6 +1 = 7 and then we move to the right digit and make it 0. So we will get 370 that is the round up value. (To get help on icse text books click here)
Similarly
2.       Round off of 342 will be: 340 because here the rounding digit is 4 and the right digit is 2 that is less than 5 so we will place a zero at its place without changing the rounding digit.
So here I tell you about a very interesting part of math. Using this we can correctly answer the question by estimation. We should get it into habit so that we may be able to frequently solve estimation and round off based problems.
In next time we will discuss about Estimating Quotients and In the next session we will discuss about Types of Numbers

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