=sum(A1:B1)
=sum(A1:B1,A2:B2) *two range
=sum(A1:B1 A1:A2) *only the overlap cell
press Ctrl many cell and input text then Ctrl + Enter to multi-input
=index(array,row_num,column_num)
=match(lookup_value,lookup_array,match_type)
=rank.eq(num,ref,order)
=mode.sngl(num1,num2...)
=choose(index_num,vaalue1,value2) *set 1 to text1 and 2 to text2
=text(value,format_text) * turn num to string