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Chapter 5—Powers, Exponents, and Roots

5-6 Engineering Notation

When you complete the work for this section, you should be able to:
  • Cite the rule for adding and subtracting numbers that use power-of-10 notation
  • Demonstrate your ability to add and subtract numbers expressed in power-of-10 notation
  • Cite the rule for multiplying and dividing numbers that use power-of-10 notation
  • Demonstrate your ability to multiply and divide numbers expressed in power-of-10 notation
  • Multiplying and Dividing Powers of Ten

    Procedure

    To multiply powers of 10:

    1. Multiply the coefficients of the factors. The result is the coefficient of the product.
    2. Add the exponents of the factors. The result is the exponent of the product.

    Of course the base of 10 remains unchanged.

    Examples of Mulitiplying Powers of Ten

     
    Use this scroll bar to view all of the examples.

    Examples and Exercises

    Multiplying Powers of Ten

    Use these interactive examples and exercises to strengthen your understanding and build your skills:

     

    Procedure

    To divide powers of 10:

    1. Divide the coefficients of the terms — numerator divided by denominator. The result is the coefficient of the quotient.
    1. Subtract the exponents of the terms — numerator minus denominator. The result is the exponent of the quotient.

    Example

    Problem
    ( 9 x 108 ) = _____
    ( 3 x 102 )
    Procedure
    1. Divide the coefficients.
    ( 9 x 108 )
    ( 3 x 102 )

    9 / 3 = 3

    1. Subtract the exponents.
    ( 9 x 108 ) = _____
    ( 3 x 102 )

    8 – 2 = 6

    1. Assemble the results
    3 x 106
    Solution
    ( 9 x 108 ) = 3 x 106
    ( 3 x 102 )

    Example

    Problem
    ( 3.6 x 108 ) = _____
    ( 2 x 10 -4 )
    Procedure
    1. Divide the coefficients.
    ( 3.6 x 108 )
    ( 2 x 10 -4 )

    3.6 / 2 = 1.8

    1. Subtract the exponents.
    ( 3.6 x 108 )
    ( 2 x 10 -4 )

    8 – ( –4 ) = 12

    1. Assemble the results
    1.8 x 1012
    Solution
    ( 3.6 x 108 ) = 1.8 x 1012
    ( 2 x 10 -4 )

    Examples and Exercises

    Dividing Powers of Ten

    Use these interactive examples and exercises to strengthen your understanding and build your skills:

     

    Procedures Review

    To multiply powers of ten:

    1. Multiply the coefficients
    2. Add the exponents

    To divide powers of ten:

    1. Divide the coefficients
    2. Subtract the exponents

    Adding and Subtracting Powers of Ten

    Adding and subtracting powers of ten can be a bit more complicated than multiplying and dividing.  The main problem is that powers of ten can be added or subtracted only when both terms have the same exponent. In other words, it is okay to add or subtract 2.1 x 102 and 1.4 x 102 because they both have the same exponent. But consider 6.8 x103 and 3.4 x 104. Those terms cannot be added or subtracted in their given form–one has to be rewritten so that its exponent is equal to the exponent of the other term.

    Important

    Powers of ten can be added or subtracted only when their exponents are equal.

     

     

    Procedures

    fig0603_04.jpg (18589 bytes)To add powers of ten:

    1. Make sure the terms have the same power of ten.
    2. Add the coefficients
    3. Assign the common power of ten

    To subtract powers of ten:

    1. Make sure the terms have the same power of ten.
    2. Subtract the coefficients
    3. Assign the common power of ten

    It is easy to add and subtract powers of ten when the exponents are already identical.

    Examples

    1.    3 x 104 + 5 x 104 = 8 x 104 2.    8.2 x 108 – 1.1 x 108 = 7.2 x 108 3.   2 x 10-3 + 4 x 10-3 = 6 x 10-3

    Examples and Exercises

    Introduction to Adding and Subtracting Powers of Ten

    Use these interactive examples and exercises to strengthen your understanding and build your skills:

    When the exponents are not the same, you must rewrite one of the terms so that the exponents are equal. It really makes no difference which terms you change—just so the exponents end up being equal. After that, simply add or subtract as in the previous examples in this lesson.

    Example

    Problem

    4 x 103 + 2 x 102 = _____

    Procedure
    1. Rewrite one of the terms so that the exponents are equal.
    4 x 103 = 40 x 102
    1. Complete the addition
    40 x 102 + 2 x 102 = 42 x 102
    Solution

    4 x 103 + 2 x 102 = 42 x 102 or 4.2 x 103

     

    Example

    Problem

    12 x 108 –  5 x 1010 = _____

    Procedure
    1. Rewrite one of the terms so that the exponents are equal.
    5 x 1010 = 500 x 108
    1. Complete the addition
    12 x 108 –   500 x 108 = – 488 x 108
    Solution

    12 x 108 –  5 x 1010 = – 488 x 108
    or – 4.88 x 1010

    Examples and Exercises

    Adding and Subtracting Powers of Ten

    Use these interactive examples and exercises to strengthen your understanding and build your skills:

    Author: David L. Heiserman
    Publisher: SweetHaven Publishing Services

    Copyright © 2007, David L. Heiserman
    All Rights Reserved