The sixth grade students donated money to the children in the disaster area. The first class donated 500 yuan, the second class donated to the first class (4/5), and the third class donated to the first class (9/10). How much did the sixth and third classes donate? ?
六年级同学给灾区的小朋友捐款，一班捐了500元，二班捐的是一班的(4/5)，三班捐的是一班的(9/10)，六三班捐款多少元？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">500 * (9/10)</gadget>
<output>450</output>

<result>450</result>