After the opening of digital TV in our county, 138 programs can be watched, which is 2 sets more than four times before the opening of digital TV. How many TV programs can only be watched before the opening of digital TV? (column equation solution)
我县开通数字电视后，能收看138套节目，比开通数字电视前的4倍还多2套，开通数字电视前只能收看几套电视节目？(列方程解答)
<gadget id="calculator">138 - 2</gadget>
<output>136</output>

<gadget id="calculator">136 / 4</gadget>
<output>34</output>

<result>34</result>