How many co-prime numbers can be formed with prime numbers less than 10?
用10以内的质数能组成互质数多少组．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2)</gadget>
<output>6</output>

<result>6</result>