Real Numbers in the Real World

Ulysses Harrison               Dunbar Vocational High School
                               3100 South King Drive
                               Chicago IL 60616
                               312-534-9000

Objectives:

Students will be able to group the set, R, of real numbers into two different 
sets:  R > 0, R < 0. 

Students will be able to use parentheses to change the order in which 
exponentiation, multiplication, division, addition and subtraction are performed 
by using the TI-34 calculator. 

Students will be able to work problems throughout the set of real numbers using 
the TI-34 calculator without preference for positive numbers. 

Materials Needed:

Set of TI-34 Calculators--one for each student.

Strategy:

Inform the students that the real number system consists of natural numbers, 
whole numbers, integers, rational numbers, and irrational numbers.  Students 
must be able to comfortably use the whole set of real numbers to perform the 
mathematics operations in order to be successful at working problems in the real 
world.  Give example problems that include numbers in the subsets of the real 
number system initially.  Have students work these problems on the calculator.   
Finally, include problems that involve all the real numbers and all the 
operations.  Have students work these problems on the calculator.  Emphasize to 
students that the calculator is only a tool for them to use.  The students must 
know the operations of mathematics for the calculator to correctly perform the 
arithmetic.  This allows the students more time to learn and become comfortable 
in applying principles of mathematics to problems and opportunities they 
encounter in the real world. 

Performance Assessment:

     a.  Give students a set of 20 problems that include parentheses, 
          exponents, multiplication, division, addition and subtraction.
     b.  Have students work the set of problems without the use of calculators.
     c.  Have students use the calculator to work the same set of problems.
     d.  Compare the scores on the two sets of problems.
     e.  Have students discuss advantages and disadvantages of using calculators
          in class.

Multicultural Application:

Calculators and real numbers can be used efficiently by all cultures.  Wise use 
of the calculator as a tool can expedite mastery of new subjects and material in 
mathematics.