James has 30 teeth. His dentist drills 4 of them and caps 7 more teeth than he drills. What percentage of James' teeth does the dentist fix?
First find the total number of teeth the dentist caps: 4 teeth + 7 teeth = 
<gadget id="calculator">4+7</gadget>
<output>11</output>
11 teeth.
Then find the total number of teeth the dentist fixes: 11 teeth + 4 teeth = 
<gadget id="calculator">11+4</gadget>
<output>15</output>
15 teeth.
Then divide that number by the total number of teeth and multiply by 100% to find the percentage of teeth he fixes: 15 teeth / 30 teeth * 100% = 50%

<result>50</result>