# Help

### Entering a formula

- Start with Excel running and displaying the worksheet containing the
data. Lets suppose that the data are in column B and that you want to put
the results of the formula in column C.
- For example you want to convert a temperature from Fahrenheit to Celsius.
The appropriate formula is:
T (C) = (T (F) - 32)*5/9

- Go to the first row containing the data and move the mouse into the
cell that should contain the result of your unit conversion, for example
cell C3.
- Type:
**=(B3-32)*5/9** and hit **enter**. The result of your
conversion will appear in cell C3.
- If you want to do the conversion for the rest of the column, you do
not need to retype the formula. Instead, go to the lower right corner of
the cell C3 and the mouse will change to a narrow
**+**. Hold the (left)
mouse button and drag the corner of the cell all the way down to the last
cell in the column, and then release the mouse. This will copy the formula
into the remaining cells of column C.
- As an alternative, you can highlight the part of column C that will
contain the results of the conversion, then go to the
**Edit** menu
and select **Fill** and then **Down**.
- Copying the formula will update the references, i.e. the formula in
cell C10 will read:
**=(B10-32)*5/9**. Sometimes it is desireable
to not update the reference to a cell, but use the content of a particular
cell for all calculations. In the formula above, you could put the constant,
32, into one cell, for example A1. Your formula then should read: **=(B3-$A$1)*5/9**.
Using $ signs makes sure that the referenced cell will not change when
you update the formula.