Simple calculation: 77*13+255*999+510.
简便计算：77*13+255*999+510．
<gadget id="calculator">77 * 13</gadget>
<output>1_001</output>

<gadget id="calculator">255 * 999</gadget>
<output>254_745</output>

<gadget id="calculator">1_001 + 254_745 + 510</gadget>
<output>256_256</output>

<result>256_256</result>