Question

How Many 3 Digit Numbers Can Formed By Using The Digits 1 To 9 If No Digit Is Repeated ?​

Answer 1

$\fbox{ \bold{ \large{Given \: }}}$

$\to$ 1 to 9 digits to make 3 digit numbers

$\fbox{ \bold{ \large{Solution :- \: }}}$

Repetition is not allowed

$\to$ The first place can be filled in 9 different ways by anyone of the 1 to 9 digits

$\to$ The second place can be filled in 8 different ways by anyone of the remaining digits

$\to$ The third place can be filled in 7 different ways by anyone of the remaining digits

By Multiplication Principal ,

Total numbers of ways = 9 × 8 × 7 = 504 ways

Hence , 504 three digit numbers can formed by using 1 to 9 digits If no digit is repeated