If A = 1/2 + 1/3 × 1/4 ÷ 1/5 and B = 1/2 ÷ 1/3 × 1/4 + 1/5, then what is the value of A – B?

A = 1/2 + (1/3 × 5/4) = 1/2 + 5/12 = 6/12 + 5/12 – 1/6... computing carefully: A = 1/2 + 5/12 – 1/6 = 9/12 = 3/4. B = (1/2 × 3) × 1/4 + 1/5 = 3/8 + 1/5 = 23/40. A – B = 30/40 – 23/40 = 7/40.