How many positive, 3-digit integers contain at least one 7?
Options
A) 171 B) 200 C) 243 D) 252 E) 271
243ontains only one 7:   7XX:  1*9*9= 
<gadget id="calculator"> 1*9*9</gadget>
<output>81</output>
81   X7X: 8*1*9= 
<gadget id="calculator">8*1*9</gadget>
<output>72</output>
72   XX7: 8*9*1= 72   243ontains two 7s:   77X: 1*1*9= 
<gadget id="calculator">1*1*9</gadget>
<output>9</output>
9   X77: 8*1*1= 8   243ontains three 7s:   777: 1   Total 243   ANS:243
<result>C</result>
How many positive, 3-digit integers contain at least one 7?