Calculation: 0.02+0.04+0.06+0.08+...+19.94+19.96+19.98=how much.
计算：0.02+0.04+0.06+0.08+…+19.94+19.96+19.98=多少．
<gadget id="calculator">0.02 + 19.98</gadget>
<output>20</output>

<gadget id="calculator">999 / 2</gadget>
<output>999/2 = around 499.5</output>

<gadget id="calculator">20 * (999/2)</gadget>
<output>9_990</output>

<result>9_990</result>