0,9 : 1/10 + 17,85 : 3 1/2 - (5 31/63 - 3 17/42) * 6,3

Решение:

1. \[ 0,9 : \frac{1}{10} = 0,9 \times 10 = 9 \]
2. \[ 3 \frac{1}{2} = \frac{7}{2} = 3,5 \]
3. \[ 17,85 : 3,5 = 5,1 \]
4. \[ 5 \frac{31}{63} = \frac{5 \times 63 + 31}{63} = \frac{315 + 31}{63} = \frac{346}{63} \]
5. \[ 3 \frac{17}{42} = \frac{3 \times 42 + 17}{42} = \frac{126 + 17}{42} = \frac{143}{42} \]
6. \[ \frac{346}{63} - \frac{143}{42} = \frac{346 \times 2}{126} - \frac{143 \times 3}{126} = \frac{692 - 429}{126} = \frac{263}{126} ≈ 2,087 \]
7. \[ 2,087 \times 6,3 ≈ 13,148 \]
8. \[ 9 + 5,1 - 13,148 = 14,1 - 13,148 = 0,952 \]

Ответ: ≈ 0,952