How to refer to the same cell in MS Excel?

Question

Let me simplify my problem as below..

1. I multiply A1 with D1 at E1.
2. Multiply A1 with D2 at E2
3. Multiply A1 with D3 at E3
.
.
.
To do this,
If I try to copy E3 and paste it at E4 (or just drag further), excel tries to do the math as A4*D4 (like 'An*Dn').
Is there any way to refer to the same cell?
Like 'A1*Dn' at En.

This will give me the flexibility to change value at one cell and reflect at many places.

Please let me know if there is any way to do it.

Thanks.

Answer 1

Change the formula to $A$1 and the A1 will not change when you copy the formula (but the Dn will). It is called absolute reference.

Answer 2

Change the A1 number only, and then double click on the left corner of the cell.
The number that in A1 will be till Bn.

Answer 3

Don't "copy & paste" the formula...

Instead, click the formula button, and enter it manually.