There are a total of 30 pieces of RMB 2 and 5 yuan, totaling 75 yuan, how many pieces of RMB 2 yuan are there?
有2元和5元的人民币共30张，总共75元，则2元的人民币有多少张．
<gadget id="calculator">5 * 30</gadget>
<output>150</output>

<gadget id="calculator">150 - 75</gadget>
<output>75</output>

<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">75 / 3</gadget>
<output>25</output>

<result>25</result>