Attempt the question, check the explanation, and continue with similar questions to build confidence before exams.
(z1 + z2) + z3 = z1 + (z2 + z3)
(z1 + z2) + z3 = z3 + (z2 + z1)
z1 + (z2 - z3) = z1 + z2 - z3
z1 + z2 = z2 + z3
Continue with nearby questions to strengthen the same chapter concept while you still have the context fresh in mind.
