24

Using the TI-73: A Guide for Teachers

Patterns and Functions

Activity—Part A

1.Ask students: Look at the row for the number of blocks. What pattern do you see? (The first number is 3 and then increases by 1.)

2.Demonstrate along with your class how to put the pattern into the TI-73.

a.Explain that this whole scenario starts with a

1-level tower that needs 3 blocks. So the first entry is 3.

[ b

b.Ask students: How many blocks do you need for a 2-level tower? (Remember, you are working on how to get from the original 3 blocks to the 4 blocks in the 2-level tower.)

c.Press \ Y.

Ask the class to tell you what Ans means. (Explain that just pressing \ indicates to the TI-73 that it needs two things to add, so it grabs the answer (in this case, 3) that you had in the line above and calls it Ans.)

d.Press b.

Explain that the number of blocks in the 1-level tower is the first entry and output on the screen (3). The number of blocks in the 2-level tower is the next output (4).

e.Press b again.

Ask the class to explain what happened. (Because you did not enter a new command, the TI-73 did the previous command again; but this time, Ans stood for the most current answer, which was 4.)

f.Ask students: How would you use the b key (this technique) to find out how many blocks you would need for a 10-level tower?

➪Have students count aloud as you press b7 more

times.

© 1998 TEXAS INSTRUMENTS INCORPORATED