1)1 1\5 *2 5\6= -4\9*2 1\4= 9\20*(-3 4\9)= -1 5\16*(-3 3\7)= 2)вычислите удобным а)38\61*61\38*(-5)= 8\27)*151\432*432\151= в) 2\7*4 1\5 * 7\2= )*(-2 7\18)*14\9=

1)
1 1/5 * 2 5/6 = 6/5*17/6 =17/5=3 2/5.
-4/9*2 1/4 = -4/9 * 9/4 = -1.
9/20*(-3 4/9) = 9/20*(-31/9)= 31/20 = 1 11/20
-1 5/16*(-3 3/7)= 21/16*24/7=9/2=4 1/2
2)
38/61 * 61/38 *(-5) = -5
(-38/27)*151/432*432/151 = (-3 8/27)
2/7 * 4 1/5 * 7/2 = 4 1/5
(-9/14) * (-2 7/18) * 14/9 = 2 7/18
Проверяй здесь - http://ru.onlinemschool.com/math/assistance/fraction/fraction_calc/.Удачи)