Among fractions (1/10), 3(3/4), (9/12), (4/15), how many fractions cannot be reduced to finite decimals.
在分数(1/10)，3(3/4)，(9/12)，(4/15)中，不能化成有限小数的是多少．
<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<result>4/15 = around 0.266667</result>