Xiaojun collected 13 sets of animal pictures, each with 4 pieces. Give 16 cards to classmates, how many cards are left?
小军收集了13套动物画片，每套4张．送给同学16张，还剩多少张？
<gadget id="calculator">4 * 13</gadget>
<output>52</output>

<gadget id="calculator">52 - 16</gadget>
<output>36</output>

<result>36</result>