How many subsets are there in a set formed from the letters of the word mathematics?

Answer 1

In a set, as it is usually defined, elements can't be repeated. "Mathematics" has 8 distinct letters, so your set would have 8 letters. The number of possible subsets (this includes the empty set, and the set itself) is two to the power 8.

Answer 2

In a set, repetition of elements is not regarded as a difference. That being the case, "mathematics" has 8 distinct letters and so there will be 2^8 = 256 subsets (including the null set).

Answer 3

15*(3,6,9,12,15 ,18,......)