The sixth grade students plan to make 50 headdresses for the graduation party. The first class did 30% of the plan, and the second class did the plan (1/2). How many have been made?
六年级同学打算为毕业联欢会做50个头饰．第一节课做了计划的30%，第二节课做了计划的(1/2)．已经做成多少个？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/10) + (1/2)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 * (4/5)</gadget>
<output>40</output>

<result>40</result>