Вычислите: (1/6-5/9)х(1/2-3/7)х7 1/5 правильно решить

(1/6 - 5/9) * (1/2 - 3/7) * 7 1/5 = - 1/5

1) 1/6 - 5/9 = 3/18 - 10/18 = - 7/18
2) 1/2 - 3/7 = 7/14 - 6/14 = 1/14
3) - 7/18 * 1/14 = - (1*1)/(18*2) = - 1/36
4) - 1/36 * 7 1/5 = - 1/36 * 36/5 = - 1/5