A triangle divides the plane into two parts. How many parts can the plane be divided into at most by 10 triangles?
一个三角形把平面分成两部分，10个三角形最多能把平面分成多少部分．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">10 * 9 * 3</gadget>
<output>270</output>

<gadget id="calculator">2 + 270</gadget>
<output>272</output>

<result>272</result>