A customer went to a store to buy shoes. He only knew that the old size of the shoes he was wearing was size 43, but he did not know the new size of the shoes he was wearing. He only knew that adding a number to the old size and dividing it by 2 was the new shoe size. ． But he remembers that his son's old shoe size is 40, and the new shoe size is 25. Now please calculate for this customer what is his new shoe size?
有位顾客到商店购鞋，仅知道自己所穿鞋子的老尺码是43码，而不知道自己所穿鞋子的新鞋号，他只知道老尺码加上一个数以后除以2就是新鞋号．但他记得他儿子穿的鞋老尺码是40码，新鞋码是25号，现在请你为这位顾客计算出他的新鞋号是多少？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 40</gadget>
<output>20</output>

<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">5 / (1/2)</gadget>
<output>10</output>

<gadget id="calculator">43 + 10</gadget>
<output>53</output>

<gadget id="calculator">(1/2) * 53</gadget>
<output>53/2 = around 26.5</output>

<result>53/2 = around 26.5</result>