There are 820 students in a certain elementary school, among which the sixth grade accounts for (3/20) and the fifth grade accounts for (1/10). How many students are there in fifth and sixth grades?
某小学有学生820人，其中六年级占(3/20)，五年级占(1/10)．五、六年级共有学生多少人？
<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(3/20) + (1/10)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">820 * (1/4)</gadget>
<output>205</output>

<result>205</result>