Since the word MATH does not have any duplicated letters, the number of permutations of those letters is simply the number of permutations of 4 things taken 4 at a time, or 4 factorial, or 24.
The word would be needed for a specific response, but here's a general one: Take the factorial of the number of letters in the word, and divide that by the product of the factorials of the counts of...
24 If we are looking at unique permutations, there would be half as many as there are stated above, as there are two o's in the word. So, in reality, there are only 12 permutations: hook hoko hkoo...
because permutations are order specific, and because there are two d's "dad" counts as only one. so it is 6 (3P3)/2 (there are two d's) so the answer is 3DAD ADD DDA