In a germination test with 50 seeds, the germination rate is 90%, how many seeds did not germinate?
用50粒种子做发芽试验，发芽率是90%，有多少粒种子没有发芽．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">50 * (1/10)</gadget>
<output>5</output>

<result>5</result>