Помогите по математике пожалуйста

(2 13/48 + 2 5/12) : 3 3/4 - 9 3/4 : 12 = 7/16.

1) 2 13/48 + 2 5/12 = 2 + 2 + 13/48 + 5/12 = 4 + 13/48 + (5 * 4)/(4 * 12) = 4 + 13/48 + 20/48 = 4 + (13 + 20)/48 = 4 + 33/48 = 4 + (3 * 11)/(3 * 16) = 4 11/16;

2) 4 11/16 : 3 3/4 = (4 * 16 + 11)/16 : (3 * 4 + 3)/4 = 75/16 : 15/4 = 75/16 * 4/15 = (5 * 15 * 4)/(4 * 4 * 15) = 5/4 = 1 1/4;

3) 9 3/4 : 12 = (9 * 4 + 3)/4 : 12 = 39/4 * 1/12 = 39/(4 * 12) = 39/48 = (3 * 13)/(3 * 16) = 13/16;

4) 1 1/4 - 13/16 = 5/4 - 13/16 = (5 * 4)/(4 * 4) - 13/16 = 20/16 - 13/16 = 7/16.

вроде правильно