Enter a formula in cell e4 to calculate how long each item has been on sale. this is calculated by subtracting the launch date in cell d4 from the data updated date in cell c20. to show the time in years, divide that result by 365. use an absolute reference to the date in cell c20. copy the formula from cell e4 to cells e5: e14.

in d4 is 3/17/2013
in c20 is 10/14/2016

any ? i have no idea what function is needed for this.