The third and fourth grades collected a total of 316 plant specimens. If the fourth grade gave 20 to the third grade, then the two grades collected the same number. How many specimens did the third grade collect?
三、四年级共采集植物标本316件，如果四年级给三年级20件，那么两个年级采集的同样多，三年级原来采集了多少件？
<gadget id="calculator">316 / 2</gadget>
<output>158</output>

<gadget id="calculator">158 - 20</gadget>
<output>138</output>

<result>138</result>