How many positive integers less than 600 can be formed using the numbers 1, 2, 3 and 5 for the digits?
Choose one:	A) 48	B) 52	C) 66	D) 68	E) 84
Notice that we can find the number of 2 and 3 digit numbers by just assuming the first digit can also be zero:   0 1 1   1 2 2   2 3 3   3 5 5   5 5 5   Number of possibilities = 5*4*4= 
<gadget id="calculator">5*4*4</gadget>
<output>80</output>
80.   Then, just add up the number of 1 digits numbers= 4, so total is  80+4= 
<gadget id="calculator"> 80+4</gadget>
<output>84</output>
84.   Answer:84
<result>E</result>
How many positive integers less than 600 can be formed using the numbers 1, 2, 3 and 5 for the digits?