Calculate (10+20+40+60+80)*(30+50+70+90)-(10+30+50+70+90)*(20+40+60+80)=how much.
计算(10+20+40+60+80)*(30+50+70+90)-(10+30+50+70+90)*(20+40+60+80)=多少．
<gadget id="calculator">10 + 20 + 40 + 60 + 80</gadget>
<output>210</output>

<gadget id="calculator">30 + 50 + 70 + 90</gadget>
<output>240</output>

<gadget id="calculator">210 * 240</gadget>
<output>50_400</output>

<gadget id="calculator">10 + 30 + 50 + 70 + 90</gadget>
<output>250</output>

<gadget id="calculator">20 + 40 + 60 + 80</gadget>
<output>200</output>

<gadget id="calculator">250 * 200</gadget>
<output>50_000</output>

<gadget id="calculator">50_400 - 50_000</gadget>
<output>400</output>

<result>400</result>