how many 5 digit nos are there if the 2 leftmost digits are odd and the digit 4 ca n ' t appear more than once in the number? could someone please provide a solution using a approach other than ( 1 - x ( none ) ) approach?  Answers: A) 24300 B) 25700 C) 26500 D) 24400 E) 26300
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">19 * 5</gadget>
<output>95</output>

<gadget id="calculator">95 * 5</gadget>
<output>475</output>

<gadget id="calculator">475 * 5</gadget>
<output>2_375</output>

<gadget id="calculator">2_375 * 10</gadget>
<output>23_750</output>

<result>A</result>
how many 5 digit nos are there if the 2 leftmost digits are odd and the digit 4 ca n ' t appear more than once in the number? could someone please provide a solution using a approach other than ( 1 - x ( none ) ) approach?
multiply(multiply(multiply(multiply(subtract(multiply(4, 5), 1), 5), 5), 5), const_10)
a . 4 is used once : oo * * 4 - - > ( 5 * 5 * 9 * 9 ) * 3 : 5 choices for the first digit as there are 5 odd numbers , 5 choices for the second digit for the same reason , 9 choices for one of the two * ( not - 4 digit ) , 9 choices for another * ( not - 4 digit ) , multiplied by 3 as 4 can take the place of any of the three last digits ( oo * * 4 , oo * 4 * , oo 4 * * ) ; b . 4 is not used : oo * * * - - > 5 * 5 * 9 * 9 * 9 : the same logic as above . 5 * 5 * 9 * 9 * 3 + 5 * 5 * 9 * 9 * 9 = 24300 . answer : a