Calculation: 1989*19901990-1990*19891989=how much.
计算：1989*19901990-1990*19891989=多少．
<gadget id="calculator">1_989 * 19_901_990</gadget>
<output>39_585_058_110</output>

<gadget id="calculator">1_990 * 19_891_989</gadget>
<output>39_585_058_110</output>

<gadget id="calculator">39_585_058_110 - 39_585_058_110</gadget>
<output>0</output>

<result>0</result>