You can then increase or decrease the the decimical place as needed. New value - old value new value. By default the results are displayed as decimal numbers.
Excel uses a default order in which calculations occur.
For example if you want to calculate 25 of 50 multiply 25 by 50. To show percentages apply the Percentage number format to the formula cells. Below is the formula to calculate the percent change in general. See Rounding issues below for more information.