A whole bag of flour weighs 20 kilograms. I ate (2/5) bags last week and (3/8) bags this week. How many kilograms of flour did you eat in two weeks?
一整袋面粉的重量是20千克，上周吃去了(2/5)袋，这周又吃去了(3/8)袋．两周共吃去面粉多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(2/5) + (3/8)</gadget>
<output>31/40 = around 0.775</output>

<gadget id="calculator">20 * (31/40)</gadget>
<output>31/2 = around 15.5</output>

<result>31/2 = around 15.5</result>