Hello my friends,

example file: http://s3.dosya.tc/server15/kOIeI1/d...rade.xlsx.html

i want to evaluate data for each lesson grades, which is higher than 80 ( + ) , less than 80 ( - )
how can i produce from this data, a summary like this:

physics : + - - + - + - ( oldest -----> newest date)
maths : - - - + + -
history : + + - + + - -