**76**

(50-59)- must be multiple of 3, 4 & 6, i.e multiple of 12- no such a number, excluded

(60-69)- must be multiple of 6 but not multiple of 3 or 4, it is not possible as any multiple of 6 will also be multiple of 3, excluded

970-79)- must be multiple of 4 nut not multiple of 3 or 6. Multiples of 4 are 72 and 76 but 72 is also multiple of 3&6 so is excluded. The only number left is **76**.