Mom wants to buy a pair of sports shoes online. Store A sells them with a 30% discount, and store B gets a discount of 45 yuan for every 100 yuan spent. Buying a pair of sports shoes with the same price tag of 280 yuan, which store is cheaper to buy at A or B? How much money can you save?
妈妈想网购一双运动鞋，甲店七折销售，乙店每满100元减45元，买一双同样标价280元的运动鞋，在甲、乙哪个店买更省钱？可以省多少钱？
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">280 * (7/10)</gadget>
<output>196</output>

<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<gadget id="calculator">280 - 90</gadget>
<output>190</output>

<gadget id="calculator">196 - 190</gadget>
<output>6</output>

<result>6</result>