During the New Year’s Day, a shopping mall holds activities. If the one-time shopping does not exceed 100 yuan, it will be charged at a 10% discount; Charged at 30% off. Mr. Wang went to the shopping mall for a one-time shopping of 500 yuan during the event, how much is the actual charge?
元旦期间，某商场做活动，若一次性购物不超过100元，则按九折收费；若超过100元不超过300元，超过100元的部分按八折收费；若超过300元，则超出部分按七折收费．王老师在活动期间到该商场一次性购物500元，则实际收费是多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">100 * (9/10)</gadget>
<output>90</output>

<gadget id="calculator">300 - 100</gadget>
<output>200</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">200 * (4/5)</gadget>
<output>160</output>

<gadget id="calculator">500 - 300</gadget>
<output>200</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">200 * (7/10)</gadget>
<output>140</output>

<gadget id="calculator">90 + 160 + 140</gadget>
<output>390</output>

<result>390</result>