To create a new input cell, just click outside an existing cell and start typing. When you have finished, press ⇧|⌤. Mathematica evaluates your input and puts the result in an output cell immediately underneath.

Here is a sample calculation. Your cursor can be anywhere in the input cell when you press ⇧|⌤. The In[n]:= and Out[n]= labels are added automatically.

5+3

You can edit existing input and press ⇧|⌤ to re-evaluate it. The new result replaces the old one in the output cell.

264/4

Go ahead and change some of the numbers in the input cell above. Then press ⇧|⌤ to redo the calculation.

19^20

If you put an explicit decimal point in your input, then Mathematica gives you an approximate numerical result. Very large and very small numbers are then shown in exponential notation.

3.^22

Exercise:
- Use the  Notebook as pocket calculator

  - Try  your own commands and save them  in a Notebook file.

         Goto:     File - Save as - type in your FileName