excel - Comparing sheets difference -

lets have following sheets. want following logic of output. if columna value of sheet2 exists or not exists, return true or false value column. @ same time want if true, if sheet1 columnb (linked columna) different sheet2 columnb output difference. see below example structure , @ bottom i'll output i'll see.

sheet1:

columna columnb          5.5 b          2.2 

sheet2:

columna columnb          1.1 d          2 

output i'd get:

sheet3

columna       columnb true            4.4 false           n/a 

try formula in sheet 3

for cell a1 type in below formula , drag copy other cells

=if(isblank(sheet2!a1), concatenate("false", "    n/a"), concatenate("true", "    ", (sheet1!a1-sheet2!a1)))