Mom and Li Ming went to the bookstore and spent 90 yuan on storybooks, 30% of the total money was used, and extracurricular exercise books were spent on the total money (2/15), how much money did mother have left?
妈妈和李明逛书店，买故事书用了90元，用去总钱数的30%，买课外练习书又用去总钱数的(2/15)，妈妈还剩下多少钱？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">90 / (3/10)</gadget>
<output>300</output>

<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 - (3/10) - (2/15)</gadget>
<output>17/30 = around 0.566667</output>

<gadget id="calculator">300 * (17/30)</gadget>
<output>170</output>

<result>170</result>