Operating the TI-80 1-21
The TI-80 recognizes implied multiplication. For example, it
understands 2p, 4SIN 45, 5(1+2), and (2×5)7 as implied
multiplication.
All calculations inside a pair of parentheses are completed
first. For example, in the expression 4(1+2), EOS first
evaluates the portion inside the parentheses, 1+2, and then
multiplies the answer, 3, by 4.
You can omit any right (closing) parenthesis at the end of an
expression. All “open” parenthetical elements are closed
automatically at the end of an expression and preceding the !
(store) or display-conversion instructions.
Note: Parentheses are also used to enclose the arguments for
certain functions, for example, NDERIV(Añ,A,6). In these
cases, parentheses do not indicate implied multiplication.
To enter a negative number, use the negation function. Press
·, and then enter the number. On the TI-80, negation is in the
fourth group in the EOS hierarchy. Functions in the first
group, such as squaring, are evaluated before negation.
For example, LXñ is a negative number (or 0); L9ñ is L81. Use
parentheses to square a negative number: (L9)ñ.
Note: Use the | key for subtraction and the · key for
negation. If you press | to enter a negative number, as in 9 p
| 7, or if you press · to indicate subtraction, as in 9 · 7, it
is an error. If you press ? A · ? B, it is interpreted
as implied multiplication (A QLB).
Implied
Multiplication
Parentheses
Negation