The calculation formula of permutation and combination is as follows: The number of all permutations of m(m≤n) elements from n different elements is called the permutation number of m elements from n different elements, which is represented by symbol A(n, m).
Extended data:
Taking out any m(m≤n) elements from N different elements and grouping them is called taking out the combination of M elements from N different elements; The number of all combinations of m(m≤n) elements from n different elements is called the number of combinations of m elements from n different elements. Represented by the symbol C(n, m).
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