Autumn was constantly misplacing her pencils.  At the start of the school year, she purchased a pack of 20 pencils.  In the first month of school, she misplaced 7 pencils, broke 3 pencils and had to throw them away, she found 4, and bought 2.  How many pencils did Autumn have left?
Autumn misplaced 7 and broke 3, so that lost her 7+3 = 
<gadget id="calculator">7+3</gadget>
<output>10</output>
10 pencils.
Autumn found 4 pencils and bought 2, so she gained 4+2 = 
<gadget id="calculator">4+2</gadget>
<output>6</output>
6 pencils.
She started with 20 pencils, lost 10 and gained 6 so she had 20-10+6 = 
<gadget id="calculator">20-10+6</gadget>
<output>16</output>
16 pencils left.

<result>16</result>