Cara mengerjakan (-45)-(-20)=-25

-(45)-(-20)=-25
-45–20=-25
-45+20=-25

( – 45 ) – ( -20 ) = – 25
– 45 + 20 = – 25

– ( -20 ) → min (-)  ketemu (-) jadi (+)
Jadi – 45 + 20 = – 25