What is the sum of the arithmetic sequence whose first term is 5, last term is 93, and the tolerance is 4.
首项是5，末项是93，公差是4的等差数列的和是多少．
<gadget id="calculator">5 + 93</gadget>
<output>98</output>

<gadget id="calculator">23 / 2</gadget>
<output>23/2 = around 11.5</output>

<gadget id="calculator">98 * (23/2)</gadget>
<output>1_127</output>

<result>1_127</result>