My mother bought 3.5 kilograms of grapes, which is 0.5 kilograms less than twice the amount of peaches. How many kilograms of peaches did my mother buy back?
妈妈买了3.5千克的葡萄，比买的桃子的2倍少0.5千克，妈妈买回了多少千克桃子？
<gadget id="calculator">3.5 + 0.5</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<result>2</result>