The original price of a tape recorder was 150 yuan, but Cong Cong bought it at a 10% discount, how much did it cost?
一台录音机原价150元，聪聪按9折买下，花了多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">150 * (9/10)</gadget>
<output>135</output>

<result>135</result>