There were 43 apples in the house, and my mother bought 15 more, and Xiaoming ate 19. How many apples are there now?
家里原来有43个苹果，妈妈又买来15个，小明吃了19个．现在还有多少个苹果？
<gadget id="calculator">15 - 19</gadget>
<output>-4</output>

<gadget id="calculator">43 + (-4)</gadget>
<output>39</output>

<result>39</result>