Master Zhang processed a batch of parts, 70 of which have been processed, and another 210 will just complete the task. What percentage of this batch of parts has been processed by Master Zhang?
张师傅加工一批零件，已经加工了70个，再加工210个就正好完成任务，张师傅已经加工了这批零件的几分之几？
<gadget id="calculator">70 + 210</gadget>
<output>280</output>

<gadget id="calculator">70 / 280</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>