For the first attempt I put in cell 'D4' the formula:

=2*C4+B2

This doesn't work because when I copy the cell it updates all the cell addresses, including the address of cell 'B2'.

For example the formula in cell 'D5' becomes:

=2*C5+B3

I can overcome this by putting a ‘$’ in front of the parts of the address I don't want to change.

In this case I don't want the '2' in the address of cell 'B2' to change, so I change the formula to:

=2*C4+B$2

Now when I drag down the formula in 'D5' becomes:

=2*C5 + B$2

You can add the ‘$’ to the row or column or both. I would normally have added it to both:

=2*C4 + $B$2

Then I could have copied the formula anywhere without worrying about either the letter or number.

Pay particular attention to this feature, you will often find it useful.

Note that it doesn't affect the 'move' operation because 'move' doesn't update the address.