There are 25 bicycles and small cars with 70 wheels in total. How many bicycles are there?
自行车和小骄车共25辆，总共有70个轮子．自行车有多少辆．
<gadget id="calculator">25 * 4</gadget>
<output>100</output>

<gadget id="calculator">100 - 70</gadget>
<output>30</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>