Xu Lu's home can receive 83 channels after installing digital TV, which is 11 more channels than the original one. How many channels were there before?
徐露家安装数字电视后共可收83个台，比原来的2倍还多11个台，原来有多少个台？
<gadget id="calculator">83 - 11</gadget>
<output>72</output>

<gadget id="calculator">72 / 2</gadget>
<output>36</output>

<result>36</result>