Congcong has a total of 19 pieces of RMB with denominations of 10 yuan and 2 yuan, totaling 78 yuan. How many sheets of 10 yuan are there?
聪聪有面额10元和2元的人民币共19张，总计78元．面额10元的有多少张．
<gadget id="calculator">10 * 19</gadget>
<output>190</output>

<gadget id="calculator">190 - 78</gadget>
<output>112</output>

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">112 / 8</gadget>
<output>14</output>

<gadget id="calculator">19 - 14</gadget>
<output>5</output>

<result>5</result>