How many odd 4-digit positive integers E that are multiples of 5 can be formed without using the digit 3?  Choose the correct choice from the following options:	A) 648	B) 729	C) 900	D) 1296	E) 3240
I choose A.   Possible n° of 1st digit: 8 (0 can't be the first number, or else it wouldn't have 4 digits. 3 is exlcuded)   Possible n° of 2nd digit: 9 (3 is excluded)   Possible n° of 3rd digit: 9 (3 is excluded)   Possible n° of 4th digit: 1 (a number is a multiple of 5 if it ends in 5 or 0, here we are asked for the odd numbers, hence the last digit can't be 0)   So, E=8*9*9*1= 
<gadget id="calculator">8*9*9*1</gadget>
<output>648</output>
648 (648)
<result>A</result>
How many odd 4-digit positive integers E that are multiples of 5 can be formed without using the digit 3?