Explanation
In this example, the goal is to calculate various percentages of the number in cell B5. This is a straightforward calculation in Excel. The main task is to correctly enter the numbers in column D as percentages. Once that is done, you can multiply the percentage by the number.
The first step is to format the cells in the range D5:D12 with the percentage number format. You can use the keyboard shortcut Control + Shift + %. Once the cells are correctly formatted, you can enter the numbers without the % operator. Excel will automatically add the % sign.
Next, enter the formula in cell E5. This formula simply multiplies the amount in B5 by the percentage in D5:
=$B$5*D5
Because the formula will be copied down, the reference to cell B5 must be an absolute reference. This locks the reference and prevents changes as the formula is copied down. Because the reference to cell D5 is relative, it will change at each new row.
The results in column E are the amounts of B5 that correspond with each percentage in column D. If the number in B5 is changed, the results in column E are updated.
Note: the percentages in column D are completely arbitrary and can be changed as desired.