The older sister and the younger sister went to the supermarket. After the older sister gave the younger sister 20 yuan, the amount of money between the two was equal. So, how much more is the elder sister than the younger sister?
姐姐和妹妹去超市，姐姐给妹妹20元钱后，两人的钱数相等．那么，姐姐原来比妹妹多了多少元．
<gadget id="calculator">20 + 20</gadget>
<output>40</output>

<result>40</result>