Найдите значение выражения: a) 20/31 * (10 1/5 - 2 4/9 + 3 7/9) - 2 5/6; б) 25,48 * 3/4 - (3,75 - 2 1/6) : 1 1/6

1. Вычисление значения выражения:

а) 20/31 * (10 1/5 - 2 4/9 + 3 7/9) - 2 5/6 = 20/31 * (51/5 - 22/9 + 34/9) - 17/6 = 20/31 * (51/5 - 56/9) - 17/6 = 20/31 * (459/45 - 280/45) - 17/6 = 20/31 * 179/45 - 17/6 = 3580/1395 - 17/6 = 716/279 - 17/6 = (1432 - 2958)/558 = -1526/558 = -763/279

б) 25,48 * 3/4 - (3,75 - 2 1/6) : 1 1/6 = 19,11 - (15/4 - 13/6) : 7/6 = 19,11 - (45/12 - 26/12) : 7/6 = 19,11 - 19/12 : 7/6 = 19,11 - 19/12 * 6/7 = 19,11 - 19/14 = 19,11 - 1,357... = 17,753...