A bucket of milk weighs 30 kilograms. The first pour out (3/10) of the bucket of milk, and the second pour out (2/5) of the bucket of milk, how many kilograms are poured out in total?
一桶牛奶，重30千克，第一次倒出这桶牛奶的(3/10)，第二次倒出这桶牛奶的(2/5)，两次一共倒出多少千克？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/10) + (2/5)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">30 * (7/10)</gadget>
<output>21</output>

<result>21</result>