Investigate 100 households, 48 households have computers, and 66 households have video cameras. If every household has at least one of these items. How many households have both computers and video cameras?
调查100户人家，有电脑的48户，有摄像机的66户．如果每一户人家至少有其中一样物品．那既有电脑又有摄像机的一共有多少户．
<gadget id="calculator">66 - 100</gadget>
<output>-34</output>

<gadget id="calculator">48 + (-34)</gadget>
<output>14</output>

<result>14</result>