Mom bought less than 20 jellies, one more for 4 and 4, and two more for 5 and 5. Think about it, how many jellies did my mother buy in total?
妈妈买回不到20个果冻，4个4个的数多一个，5个5个的数多2个，想一想，妈妈一共买了多少个果冻？
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">20 - 3</gadget>
<output>17</output>

<result>17</result>