Question

Решите (2 2/3 - -4 3/4) * 19,2

Answer 1

(2 2/3 - 4 3/4) * 19,2 = - 40
1) 2 2/3 - 4 3/4 = 2 8/12 - 4 9/12 = - (4 9/12 - 2 8/12) = - 2 1/12
2) - 2 1/12 * 19,2 = - 25/12 * 19,2 = - 25 * 19,2 : 12 = - 40 

Пояснения:
2/3 = (2*4)/(3*4) = 8/12 - доп.множ. 4
3/4 = (3*3)/(4*3) = 9/12 - доп.множ. 3
2 1/12 = (2*12+1)/12 = 25/12