A classmate learns to write, and he asks himself to practice 8 sheets of paper every day on average. From Monday to Thursday, I have practiced 9 sheets of paper every day. I didn’t practice on Friday, and I practiced 10 sheets on Saturday. How many sheets should I practice on Sunday to meet his requirements.
一个同学学写字，他要求自己平均每天练8张纸．从星期一到星期四每天都已练了9张纸，星期五有事没有练，星期六练了10张，那么星期天要练多少张才能达到他的要求．
<gadget id="calculator">8 * 7</gadget>
<output>56</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">36 + 10</gadget>
<output>46</output>

<gadget id="calculator">56 - 46</gadget>
<output>10</output>

<result>10</result>