Step-by-step explanation:
1(a) -4 + 7....is the same as... 7 - 4 = 3
(b) -2 - 9 = -11....for an easier trick...you just say..( 2 + 9 )= 11..then after obtaining your answer..put the negative sign(-) on your answer..(its only applicable if the numbers in the sum are all negative)
(c) -6(3) = -6 × 3
= -18
