In a class of 30 students, the teacher polls the students on their favorite subject. 1/5 of the students like Math, and 1/3 like English. 1/7 of the remaining students like Science. The rest don’t have a favorite subject. How many students don’t have a favorite subject?
30 x 1/5 = 
<gadget id="calculator">30*1/5</gadget>
<output>6</output>
6 students like Math.
30 x 1/3 = 
<gadget id="calculator">30*1/3</gadget>
<output>10</output>
10 students like English.
So, 6 + 10 = 
<gadget id="calculator">6+10</gadget>
<output>16</output>
16 students like either Math or English.
Thus, 30 - 16 = 
<gadget id="calculator">30-16</gadget>
<output>14</output>
14 students neither like Math nor English.
Since 1/7 of the remaining like Science, therefore 14 x 1/7 = 
<gadget id="calculator">14*1/7</gadget>
<output>2</output>
2 students like Science.
Hence, 14 - 2 = 
<gadget id="calculator">14-2</gadget>
<output>12</output>
12 students neither likes the 3 subjects.

<result>12</result>