Mathematical Operations; Addition And Subtraction - Commodore 128 System Manual

Let's say that you want to add the word COMMODORE in front of
the number 128. Just move the cursor so that it is blinking on the
" 1 " in 128. Hold down the SHIFT and INST/DEL keys until you
have enough room to type in COMMODORE (don't forget to leave
enough room for a space after the E). Then type in the word
COMMODORE.

MATHEMATICAL OPERATIONS

If you want to delete something in a line (including extra blank
spaces), move the cursor to the character following the material
you want to remove. Then hold down the INST/DEL key by itself.
The cursor will move to the left, and characters or spaces will be
deleted as long as you hold down the INST/DEL key.
Mathematical Operations
You can use the PRINT command to perform calculations like
addition, subtraction, multiplication, division and exponentiation.
You type the calculation after the PRINT command.

Addition and Subtraction

Try typing these examples:
PRINT 6 + 4 RFTUHN
PRINT 50 - 20
PRINT 10 + 1 5 - 5
PRINT 75 - 100 RETURN
PRINT 30 + 40,55 -
PRINT 30 + 40;55 - 25
Notice that the fourth calculation (75-100) resulted in a negative
number. Also notice that you can tell the computer to make more
than one calculation with a single PRINT command. You can use
either a comma or a semicolon in your command, depending on
whether or not you want your results printed tabulated or next to
each other.
3-20
b f t iib n
HFtllPM
b e t u hm