There are 40 pieces of chalk in a box, (1/8) was used on the first day, and (3/10) was used on the second day, how many pieces of chalk were used in two days?
一盒粉笔共40支，第一天用了它的(1/8)，第二天用了它的(3/10)，两天一共用了多少支粉笔？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/8) + (3/10)</gadget>
<output>17/40 = around 0.425</output>

<gadget id="calculator">40 * (17/40)</gadget>
<output>17</output>

<result>17</result>