1) Resolva as operações com números inteiros/racionais:
a) – 8 – (– 20) + (– 4) . (– 2) =
( ) 28 ( ) 4 ( ) 76 ( ) 22 ( ) 20

b) (– 23) – ( – 18) ÷ 6 – 4 . 7 =
( ) 52 ( ) 47 ( ) 76 ( ) – 47 ( ) – 52

c ) – =
( ) ( ) ( ) ( ) ( ) 1
d) × =
( ) ( ) ( ) ( ) ( ) 1