Hongxing Primary School planted 300 trees last year, and the survival rate was 95%. How many trees did not survive?
红星小学去年植树300棵，成活率是95%，有多少棵没有成活？
<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">1 - (19/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">300 * (1/20)</gadget>
<output>15</output>

<result>15</result>