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					                             Rounding Whole Numbers
     When you complete the work for this section, you should be able to:
            Demonstrate how to round whole-number values to a given place value.

We often need to estimate values of whole numbers. Sometimes, for example, we say that
there are 30 people in the class when, in fact there are 32. Numbers that are estimated are
usually easier to work with and allow some "wiggle room" for accuracy. When it comes to
estimating the number of people in a crowd, for instance, there is no point in trying to report
exactly 1,234 people when and estimated value of 1,200 will suffice. So we commonly round off
numbers when it is simpler, and actually more reasonable, to cite estimated values.

Vaules that are estimated in this way are said to be rounded or rounded off.

       Is 122 closer to 120 or to 130? It is closer to 120. So we can round 122 down to 120.

       Is 127 closer to 120 or to 130? It is closer to 130, so we can round 127 up to 130.

       Is 125 closer to 120 or to 130? It is right in the middle. By convention, however, we
        round upward when the value is exactly between the two choices. So we round 125 is
        rounded upward to 130.

                                             Procedure

     Step 1: Determine which digit is to be rounded
             This determines how accurate we want to make the estimated number.
             The number to be rounded is specified by its place value—to tens, hundreds,
             thousands, and so on.
     Step 2: Look at the digit immediately to the right of the rounding digit.

            If the digit immediately to the right of the rounding digit is less than 5, then do
             not change the rounding digit.

            If the digit immediately to the right of the rounding digit is 5 or greater, then
             increase the rounding digit by 1.

     Step 3: Change all digits to the right of the rounding digit to zero.

Example 1

The Problem: Round 6,734 to the nearest hundred.
Step 1: Determine which digit is to be rounded.
6,734
Step 2: Look at the digit immediately to the right of the rounding digit.
6,734
This digit is less than 5, so the rounding digit ( 7) remains unchanged.
Step 3: Change all digits to the right of the rounding digit to zero.
6,700
The Solution: So 6,734 rounded to the nearest hundred is 6,700.



Example 2

The Problem: Round 13,874 to the nearest thousand.
Step 1: Determine which digit is to be rounded.
13,874
Step 2: Look at the digit immediately to the right of the rounding digit.
13,874
This digit is greater than 5, so the rounding digit ( 3 ) is increased to 4.
14,874
Step 3: Change all digits to the right of the rounding digit to zero.
14,000
The Solution: So 13,874 rounded to the nearest thousandth is 14,000.



Example 3

     Problem
     Round 125,000 to the nearest ten-
     thousand.

     Procedure
                                                    125,000
         1. Determine which digit is to be
              rounded.

                                                    125,000
         2. Look at the digit immediately to        This digit is equal to 5, so the rounding
              the right of the rounding digit.      digit ( 2 ) is increased to 3.
                                                    135,000
                                                    130,000
         3. Change all digits to the right of the
              rounding digit to zero.

     Solution
     So 125,000 rounded to the nearest ten-
     thousand is 130,000




http://www.waybuilder.net/sweethaven/Math/pre-algebra/PreAlg0102/default.asp?iNum=0103

				
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