In the triangle ABC, it is known that ∠A=60°, ∠B is 20° smaller than ∠A, what is the degree of ∠C?
在三角形ABC中，已知∠A=60°，∠B比∠A小20°，∠C是多少度？
<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">180 - 60 - 40</gadget>
<output>80</output>

<result>80</result>