A, B, C and D, how many different ways do these five children play badminton? Ruojia

1, A, B, C, D and E play badminton, and each child can choose to match any of the other four, so there are always 5×4=20 different combinations.

2. If A wants to match one of B, C, D and E, there are four possibilities for A's choice.

3. Suppose A chooses B, then the remaining three people (C, D, E) can match each other, and * * * has 3×2=6 different combinations. Similarly, if A chooses to match one of C, D and E, there are six different combinations. So there are 4×(6+6+6)= 144 different ways of playing.