Texas Instruments TI-99/4A - Page 124

The parentheses keys are important in complex
math problems to tell the computerwhich part
of a problem to perform first. You can demon
strate this on your system now.
First press ENTER to start a new line. Now, type
PRINT 2+ 2*4
and press ENTER. The computer will calculate
and display its answer (10) on the screen.
SCREEN 2
Now, type
PRINT(2 + 2)*4
and be sure to include the parentheses.
SCREEN 3
Now press ENTER. What happens?
Strange, you say! This time, the computer
printed a different answer (16).
SCREEN 4
Actually, the computer iscorrect in both cases.
The first time, it multiplied 2 by 4 to produce 8,
then added 2 to get the sum of 10. In the second
problem, the computer performed the calcula
tion that was inside the parentheses first: it
added 2 and 2 to get the sum of 4, then multi
plied that sum by 4 to get a final answer of 16.
Beforestarting the next exercise, type CALL
CLEAR and press ENTER to clear the screen.
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