The weight of 1 pineapple plus 1 pear is equal to the weight of 7 peaches, and the weight of 2 pears is equal to the weight of 4 peaches. So, the weight of 1 pineapple is equal to the weight of how many peaches?
1个菠萝加1个梨的重量等于7个桃子的重量，2个梨的重量等于4个桃子的重量．那么，1个菠萝的重量等于多少个桃子的重量？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">7 - 2</gadget>
<output>5</output>

<result>5</result>