First steps

When you first start the calculator, which can be done by pressing the ON button, you will be greeted by a prompt. Notice also that above the screen a RUN prompt is displayed. This means that the calculator is in RUN mode, what this means will be explained later, but for now we will always want to be in RUN mode. If you are not in RUN mode, you can switch to it by pressing the MODE key until the RUN prompt is displayed.

Introducing something like

2+2

and pressing enter will give you the expected result:

4

To discard the result simply press the red CL, shorthand for clear, button at the right of the calculator. Now, with a fresh screen, you could even write something like:

2+2*2

obtaining

6

And any other expression you could expect of a calculator. But the real power of the PC-1500 is that it can run any BASIC program. Introducing, for example:

PRINT "Hello, World!"
The spaces are optional, they make the program more readable, but could slow you down when typing.

will produce the expected output:

Hello, World!

We can also assign values to variables and print them:

A=20
PRINT A

will output

20

In this fashion we can only execute one line of program at a time, in the following chapters we will see how to write multi-line programs.