we will write year in column B and column c respectively
2017 and 2018
then we will add months of year from January to December in the cells range from A2 to A13
then we will choose cell g5 and will write the diffrence formula
g5=attendance of 2018 - attendance of 2017"
we put "=" sign to put an formula in excel
then finally we will use fill handle and drag it from g6 to g12
to copy the difference formula
look at attached file
