Technology objective : After discussion of order of operations and the "getting to know your lab" worksheets, students should have some time to be introduced to how both the TI-81 and TI-34 and a regular calculator perform mathematical operations.
Lesson : Students can use a regular calculator and a scientific calculator to compare answers to the following problem.
Example 1) 3 x 2 - 6 / 3
Have the students perform the example using the TI-81 calculator and perform the problem using a regular calculator.
TI-81 calculator answer = ____
Regular calculator answer = _____
Which is right? Have students discuss which calculator gives the correct answer by having them work the problem out by hand in their journals and describe why the calculators gave each particular answer. Have a student explain to the class why there is a need for consistency. Give the students a few more problems to try. A good idea is to have the students working in pairs, one using the TI-34 and one using the TI-81.
Now is a good time to ask the student how to solve the following problem:
Have everyone try the problem. More than likely the answers will vary. Stress the need for consistency. Suggest entering parenthesis in the numerator and denominator. Have them try the problem again using both calculators.
Make sure the students know that in the TI-34 they will have to enter all the information first, then press enter. Stress that parenthesis can also be entered but they will have to close the parenthesis.
Make sure students know to enter all information as it is presented. Parenthesis will show up.
(Game) - "Four"
Students will need to get a partner. Each set of two will be responsible for creating the numbers from 0 - 10 by using four fours and any operations. *Remind them to use parenthesis.
Students will experiment using their knowledge of order of operations in an assignment where they have to guess where to put the parenthesis in order to get the desired answers. This assignment is in the Merrill Pre-Algebra book on page 17 (problems 43 - 46).