Вычислите 2-3 1/7×(2-1 9/11)÷8/21

2-3 1/7×(2-1 9/11)÷8/21 = 2 – 3 целых 1 / 7 * ( 2 – 1 целая 9 / 11 ) / ( 8 / 21 ) = 2 – ( 3 * 7 + 1 ) / 7 * ( 2 – ( 1 * 11 + 9 ) / 11 ) / ( 8 / 21 ) = 2 – ( 21 + 1) / 7 * ( 2 – ( 11 + 9 ) / 11 ) / ( 8 / 21 ) = 2 – 22 / 7 * ( 2 – 20 / 11 ) / ( 8 / 21 ) = 2 – 22 / 7 * ( 2 * 11 - 20 ) / 11 * ( 21 / 8 ) = 2 – 22 / 7 * ( 22 – 20 ) / 11 * ( 21 / 8 ) = 2 – 22 / 7 * 2 / 11 * ( 21 / 8 ) = 2 – 2 / 7 * 2 / 1 * ( 21 / 8 ) = 2 – 4 / 7 * ( 21 / 8 ) = 2 – 1 / 1 * ( 3 / 2 ) = 2 – 3 / 2 = 2 – 1 , 5 = 0 , 5 Ответ: 1 / 2 = 0 , 5