Question

How many four digit numbers can be formed by using the digits 1 to 9 if repetition of digits is not allowed.... don't spam and give correct answer

Answer 1

Hi friends

Here is your answer

9P4

= 9!/(9-4)!

= 9!/5!

$= \frac{9 \times 8 \times 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}{5\times4 \times 3 \times 2 \times 1} \\ \\ = 72 \times 42\\ \\ =3024$

Hope it helps you to

@ MSD