9 3/4×12+17 2/3 ×11=?,8 1/6×3-2 1/9×3=?,7 1/5×5+2 1/10×5=?,2 5/11×2/3+2/3×3 15/22=?.

1)

2 1/2*(2/15-3 5/6)-2 3/4 = -12,  

1. 2/15-3 5/6 = 2/15-23/6 = 4/30-115/30 = -111/30 = - 37/10 = - 3 7/10,

2. 2 1/2 * (- 3 7/10) = - 5/2 * 37/10 = - 37/4 = - 9 1/4,

3. - 9 1/4 - 2 3/4 = - 11 4/4 = - 12,

2)

-1 1/7*(4/5+19/20)*(6 5/6+4 2/3) = - 23 1/3,

1. 4/5+19/20 = 16/20+19/20 = 35/20 = 7/4 = 1 3/4,

2. -1 1/7 * 1 3/4 = - 8/7 * 7/4 = - 8/4 = - 2,

3. 6 5/6 + 4 2/3 = 6 5/6 + 4 4/6 = 10 10/6 = 11 4/6 = 11 2/3,

4. -2 * 11 2/3 = -2 * 35/3 = - 70/3 = - 23 1/3,

3)

(6 3/8-2 3/4)*(-4)+7/18×9 = - 11,

1. 6 3/8 - 2 3/4 = 6 3/8 - 2 6/8 = 5 11/8 - 2 6/8 = 3 5/8,

2. 3 5/8 * (-4) = - 29/8 * 4 = - 29/2 = - 14 1/2,

3. 7/18 * 9 = 7/2 = 3 1/2,

4. - 14 1/2 + 3 1/2 = - 11,

4)

9 1/6:(4 1/3-8)+24*3/8 = 6 1/2,

1. 4 1/3 - 8 = 4 1/3 - 7 3/3 = - 3 2/3,

2. 9 1/6 : (- 3 2/3) = - 55/6 : 11/3 = - 55/6 * 3/11 = - 5/2 = - 2 1/2,

3. 24 * 3/8 = 3 * 3 = 9,

4. - 2 1/2 + 9 = - 2 1/2 + 8 2/2 = 6 1/2

Пошаговое объяснение: