A rope is 150 meters long, Xiao Ming used the full length (2/5) on the first day, and used the full length (3/10) on the second day, how many meters are left?
一根绳子长150米，小明第一天用了全长的(2/5)，第二天用了全长的(3/10)，还剩下多少米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

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

<gadget id="calculator">150 * (7/10)</gadget>
<output>105</output>

<gadget id="calculator">150 - 105</gadget>
<output>45</output>

<result>45</result>