=3-2
= 1
(2) The original formula =1/4×12-1/2×12+1/6×12.
=3-6+2
=- 1
(3) The original formula = (-1000-2 )×17 = (-1000 )×17-2×17.
=- 17000-34
=- 17034
Sorry, it's overdue, but I'd be happy to add it.