A pile of steel pipes, with 4 on the top layer and 10 on the bottom layer, with a difference of 1 between the two adjacent layers, how many steel pipes in this pile
一堆钢管，最上层4根，最下层10根，相邻两层均相差1根，这堆钢管共多少根
<gadget id="calculator">4 + 5 + 6 + 7 + 8 + 9 + 10</gadget>
<output>49</output>

<result>49</result>