Calculate the sum of 1+2+3+...+97+98+99.
计算1+2+3+…+97+98+99的和．
<gadget id="calculator">100 * 49</gadget>
<output>4_900</output>

<gadget id="calculator">4_900 + 50</gadget>
<output>4_950</output>

<result>4_950</result>