Calculate with a simple method: 301*302-300*303.
用简便方法计算：301*302-300*303．
<gadget id="calculator">301 * 302</gadget>
<output>90_902</output>

<gadget id="calculator">300 * 303</gadget>
<output>90_900</output>

<gadget id="calculator">90_902 - 90_900</gadget>
<output>2</output>

<result>2</result>