(1/2+1/3) × (1/5-1/4) найти алгебрическое выражение

(1/2 + 1/3) * (1/5 - 1/4) = - 1/24

1) 1/2 + 1/3 = 3/6 + 2/6 = 5/6
2) 1/5 - 1/4 = 4/20 - 5/20 = - 1/20
3) 5/6 * (- 1/20) = - 1/24