2 1/2 + x = 5/6 3 8/9 + x =

2 1/2 + x = 5/6;

х = 5/6 - 2 1/2;

х = 5/6 - 5/2;

х = 5/6 - 15/6;

х = -10/6;

2 1/2 + (-10/6) = 5/6;

5/2 - 10/6 = 5/6;

15/6 - 10/6 = 5/6;

5/6 = 5/6.

3 8/9 + x = 5/6;

35/9 + х = 5/6;

х = 5/6 - 35/9;

х = 15/18 - 70/18;

х = - 55/18;

3 8/9 + (-55/18) = 5/6;

35/9 - 55/18 = 5/6;

70/18 - 55/18 = 5/6;

15/18 = 5/6;

5/6 = 5/6.

1 1/2 : x = 1 1/2;

х = 1 1/2 : 1 1/2;

х = 1;

1 1/2 : 1 = 1 1/2;

1 1/2 = 1 1/2.

х : 6 8/9 = 3/4;

х = 3/4 * 6 8/9;

х = 3/4 * 62/9;

х = 62/12;

62/12 : 6 8/9 = 3/4;

62/12 : 62/9 = 3/4;

62/12 * 9/62 = 3/4;

3/4 = 3/4.