Question

The number of natural numbers less than $1000$ in which no two digits are repeated is

• A. $738$
• B. $585$
• C. $837$
• D. $720$

Answer 1

Answer: (B)

$585$

Answer 2

Number of one digit natural number $= 9$ Number of two digit natural numbers with different digits $= 9 \times 8$ Number of three digit natural number with different digits $= 9 \times 8 \times 7$ Total number of natural number $