Вычислите : 2 - 3 1/7 * ( 2 - 1 9/11 ) : 8/21

2 - 3 1/7 * (2 - 1 9/11) : 8/21 = 1/21) 2 - 1 9/11 = 1 11/11 - 1 9/11 = 2/112) 3 1/7 * 2/11 = 22/7 * 2/11 = (2*2)/(7*1) = 4/73) 4/7 : 8/21 = 4/7 * 21/8 = (1*3)/(1*2) = 3/2 = 1 1/24) 2 - 1 1/2 = 1 2/2 - 1 1/2 = 1/2