1-6 Operating the TI-80
In most places where a value is required, you can use an expression to enter the
value. You can enter instructions, which initiate an action, on the Home screen
or in the program editor (Chapter 10).
An expression is a complete sequence of numbers, variables,
functions, and their arguments that evaluate to a single
answer. For example, prñ is an expression. On the TI-80, you
enter an expression in the same order as you would write it.
You can create expressions on the Home screen to calculate
an answer. In most places where a value is required, you can
use an expression to enter the value.
To create an expression, you enter numbers, variables, and
functions from the keyboard and menus. An expression is
completed when you press ¸, regardless of the cursor
location. The entire expression is evaluated according to
Equation Operating System (EOSTM) rules, and then the
answer is displayed.
Note: EOS rules determine the order in which operations are
completed (page 1-20).
Most TI-80 functions and operations are symbols with several
characters in them. You must enter the symbol from the
keyboard or menu. You cannot spell it out. For example, to
calculate the log of 45, you must press l 4 5. You cannot
type in the letters L O G. (If you type LOG, the TI-80 interprets
the entry as implied multiplication of the variables L, O, and G.)
Calculate 3.76 ÷ (-7.9 + ‡5) + 2 log45.
3.76 e c · 7.9 «
y ] 5 d « 2 l 45
¸
To enter more than one expression or instruction on a line,
separate them with a colon (:). They are all stored together in
Last Entry (page 1-15).
Entering Expressions and Instructions
Expressions
Entering an
Expression
Multiple Entries
on a Line