One plank is 40 cm long and the other is 50 cm long. Nail them together in the middle to form a large plank. The length of the part nailed together in the middle is 10 cm. How many centimeters is the length of the nailed plank?
一块木板长40厘米，另一块木板长50厘米，把他们的中间钉在一起成一块大木板，中间钉在一起的部分长是10厘米，钉成的大木板长是多少厘米？
<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">40 + 40</gadget>
<output>80</output>

<result>80</result>