速算24点，

1: 9 - (7 - 10) 5 2: 9 - ((7 - 10) 5) 3: 9 - (5 (7 - 10)) 4: 9 - 5 (7 - 10) 5: 9 + (5 (10 - 7)) 6: 9 + 5 (10 - 7) 7: 9 + (10 - 7) 5 8: 9 + ((10 - 7) 5) 9: (5 (10 - 7)) + 9 10: 5 (10 - 7) + 9 11: (10 - 7) 5 + 9 12: ((10 - 7) 5) + 9