What are the permutations and combinations of 6 out of 10

Arrangement is to select 6 out of 10 and perform the full arrangement. It can be abbreviated as a10 6 (well, you can't type it here, that is: 10!) /6！=10*9*8*7*6*5

The combination is to choose 6 is c10 6 (still can't play, hey) The calculation is: (10*9*8*7*6*5) (1*2*3*4*5*6).

If the permutation is limited to natural numbers, and there are 0s out of these 10 numbers, it is a classification to be classified, divided into 0 and non-0

The first category: there is no 0 in the 6 numbers (that is, there are 9 numbers left in the 10 numbers to choose), then the remaining 9 numbers are 6 out of 9, and then all are arranged. 9！/6！=

Category 2: 0 out of 6 numbers, then there are 9 numbers left.

Step 1: 0 cannot be in the first place, then there are 5 positions to choose from, c5 1=5

Step 2: Choose 5 from the remaining 9 numbers, and then arrange the remaining 5 positions, c9 5 *5!=a9 5=9*8*7*6*5

The result is 5*(9*8*7*6*5).

Permutation 10*9*8*7*6*5 Permutation is to multiply from 10 and multiply back by 6 numbers.

Combo (10*9*8*7*6*5) (1*2*3*4*5*6) Combo is to multiply 6 numbers from 10 and multiply by 6 digits, then divide by 1 and multiply 6 digits forward. Got it?

The arrangement of 6 out of 10 is 10*9*8*7*6*5 combinations, which is 10! /(6! *4!)

Formulas for permutations and combinations can't be typed, you look here.

4 out of 10 has a(10,4) = 10*9*8*7 = 5040 permutations.

a-j 10 letters 4 letters have 5040 possible permutations, and 4 out of 10 have c(10,4) = 210 combinations.

If it can be repeated, it is 10 10 10 10 = 1000 kinds, and if it can't be repeated, there are 10 9 8 7 = 5040 kinds.

There are a(10,4)=10*9*8*7=5040 permutations.

There are c(10,4)=5040 24=210 combinations, that is, the alphabetical order is not considered.

If there is a sequence requirement, it is 10*9*8*7, and if there is no order requirement, it is (10*9*8*7) (4*3*2*1).

4 out of 10 has a(10,4) = 10*9*8*7 = 5040 permutations.

a-j 10 letters 4 letters have 5040 possible permutations, and 4 out of 10 have c(10,4) = 210 combinations.

If the letters can overlap, yes.

10,000 species.

Permutation = 30 * 29 * 28 * 27 * 26 * 25 * 24 * 23 * 22 = 29 * 26 * 25 * 23 * 33

I hope it will be helpful to you, if you don't understand anything, you can consult the teacher Oh By the way, move your little hand to give the teacher a thumbs up, thank you