You can edit data in cells this in several ways:

There are several operators that could be used in formulas.

If you simply need to perform a calculation, you can use the Formula bar as a calculator.

You can enter nonrelative references (absolute or mixed) manually by inserting dollar signs in the appropriate positions, or you can use a handy shortcut - F4 key.

You can use "Copy" (Ctrl+C) and "Paste" (Ctrl+V) options, but there is faster way to "copy" a formula to multiple adjacent cells.

This tip describes how to use fractions simply.

If you need to date-stamp or time-stamp your worksheet, Excel provides two shortcut keys that do this for you:

A simply way to apply number formatting is to use shortcut keys.
This tip summarizes the shortcut-key combinations that you can use to apply common number formatting to the selected cells or range.

Often, data imported into an Excel worksheet contains excess spaces or strange (often unprintable) characters. There are two handy functions TRIM and CLEAN to cleanup such data.