How many three-digit numbers are there such that all three digits are different and the first digit and last digit is not zero? Choices: A) 576 B) 648 C) 720 D) 729 E) 810
All three digits are different and first digit is not zero.   So first digit can be filled in 8 ways.   And, second digit can be filled in 9 ways.   And, third digit can be filled in 8 ways.   Total ways = 8*9*8= 
<gadget id="calculator">8*9*8</gadget>
<output>576</output>
576   Hence option (576).
<result>A</result>
How many three-digit numbers are there such that all three digits are different and the first digit and last digit is not zero?