The Experimental Primary School donated a total of 21,000 yuan in the activity of "giving love to the earthquake-stricken areas". Among them, the donations of the first and second grades accounted for (1/3) of the total donations of the whole school, and the donations of the fifth grade accounted for (3/7) of the donations of the third, fourth, fifth and sixth grades. May I ask: How much is the donation for the fifth grade?
实验小学在为"地震灾区献爱心"活动中共捐款21000元．其中一、二年级捐款占全校捐款总数的(1/3)，五年级捐款数是三、四、五、六年级捐款数的(3/7)．请问：五年级捐款多少元？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">21_000 * (2/3) * (3/7)</gadget>
<output>6_000</output>

<result>6_000</result>