The school buys back 38 bottles of red ink and 14 bottles of blue ink. How many bottles of red ink will the school buy? The number of bottles of red ink is three times that of blue ink.
学校买回红墨水38瓶，蓝墨水14瓶，学校还要买多少瓶红墨水，红墨水的瓶数就是蓝墨水的3倍．
<gadget id="calculator">14 * 3</gadget>
<output>42</output>

<gadget id="calculator">42 - 38</gadget>
<output>4</output>

<result>4</result>