I have to write 40 large characters every day, 15 in the morning, and 3 more in the afternoon than in the morning. How many pieces are left unwritten every day?
天天要写40张大字，上午写了15张，下午比上午多写了3张．天天还剩多少张没写？
<gadget id="calculator">15 + 3 + 15</gadget>
<output>33</output>

<gadget id="calculator">40 - 33</gadget>
<output>7</output>

<result>7</result>