77

45 - 27 : 9 = 45 - 3 = 42

6 * 8 + 63 : 7 = 48 + 9 = 57

56 : (78 - 70) = 56 : 8 = 7

(100 - 28) : 8 = 72 : 8 = 9

9 * (49 - 40) = 9 * 9 = 81

64 : 8 * 3 = 8 * 3 = 24