In Algematics, the basic operations: +,
-, ×
and ÷ are not like similar buttons
on a calculator. They work on algebraic expressions and equations as well as
numbers.

The operator buttons:
combine two things:

1. The selected number, expression or equation, and

2. the contents of the input box:

**Example 1**: The input box contains the number 4, then
clicking once does this:

(The answer can be calculated by clicking
, which is similar to the '=' key on a calculator.)

**Example 2**: The input box contains the equation: 3p + 2q
= 15, then clicking once does
this:

**Example 3**: The input box contains the expression: x-5,
then clicking once does this:

**Example 4**: The input box contains 2x, then clicking
once does this:

**Example 5**: The input box contains the expression: 4r +
1, then clicking once does this:

**Example 6**: The input box contains the number 4, , then
clicking once does this: