Using an absolute cell reference
Say you receive some entertainment coupons offering a 7 percent discount for video rentals, movies, and CDs. How much could you save in a month by using the discounts?
Then in cell D4, type =C4*. Remember that this relative cell reference will change from row to row.
Enter a dollar sign ($) and D to make an absolute reference to column D, and $9 to make an absolute reference to row 9. Your formula will multiply the value in cell C4 by the value in cell D9.