Answer:
There are 70 possible 4 digit combinations without repeating a number in the same combination.
Step-by-step explanation:
{1,2,3,4} {1,2,3,5} {1,2,3,6} {1,2,3,7} {1,2,3,8} {1,2,4,5} {1,2,4,6} {1,2,4,7} {1,2,4,8} {1,2,5,6} {1,2,5,7} {1,2,5,8} {1,2,6,7} {1,2,6,8} {1,2,7,8} {1,3,4,5} {1,3,4,6} {1,3,4,7} {1,3,4,8} {1,3,5,6} {1,3,5,7} {1,3,5,8} {1,3,6,7} {1,3,6,8} {1,3,7,8} {1,4,5,6} {1,4,5,7} {1,4,5,8} {1,4,6,7} {1,4,6,8} {1,4,7,8} {1,5,6,7} {1,5,6,8} {1,5,7,8} {1,6,7,8} {2,3,4,5} {2,3,4,6} {2,3,4,7} {2,3,4,8} {2,3,5,6} {2,3,5,7} {2,3,5,8} {2,3,6,7} {2,3,6,8} {2,3,7,8} {2,4,5,6} {2,4,5,7} {2,4,5,8} {2,4,6,7} {2,4,6,8} {2,4,7,8} {2,5,6,7} {2,5,6,8} {2,5,7,8} {2,6,7,8} {3,4,5,6} {3,4,5,7} {3,4,5,8} {3,4,6,7} {3,4,6,8} {3,4,7,8} {3,5,6,7} {3,5,6,8} {3,5,7,8} {3,6,7,8} {4,5,6,7} {4,5,6,8} {4,5,7,8} {4,6,7,8} {5,6,7,8}
