There are 156 girls in the school choir, and the number of girls is twice the number of boys. How many boys are there in the choir?
学校合唱团有女生156人，女生人数是男生人数的2倍．合唱团有男生多少人？
<gadget id="calculator">156 / 2</gadget>
<output>78</output>

<result>78</result>