#### Use a formula on the output of a condition

`=AVERAGE(FILTER(A2:A25, A2:A25>0))`

#### Select a complete row or column in a formula

`=AVERAGE(B:B)`

#### Count the number of cells

`=COUNTA(B:B)`

#### Only count cells that meet a certain condition

`=COUNTIF(B:B, "Yes")`

#### Get the data from a cell with more than one condition (use shift-ctrl-enter to activate formula, note the ampersands)

`=INDEX(C:C,MATCH(B2&"value",A:A&B:B,0))`

#### (Excel only): convert seconds to a hh:mm:ss notation

Divide the number of seconds by 86400 (number of seconds in a day) –> format cell –> custom –> enter ‘hh:mm:ss’