A watermelon can be cut vertically 9 times, how many pieces can be cut at most.
一只西瓜竖直切9刀，最多可切多少块．
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 + 1 + 2</gadget>
<output>4</output>

<gadget id="calculator">1 + 1 + 2 + 3</gadget>
<output>7</output>

<gadget id="calculator">1 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9</gadget>
<output>46</output>

<result>46</result>