A, B, and C jointly bought several notebooks with the same money. Due to personal needs, A took 5 more notebooks than B, and C took 4 more notebooks than B. Later, A paid B 4 yuan, and C should pay How much is B?
甲，乙，丙花同样的钱合伙买了笔记本若干，由于个人需要，甲比乙多拿了5本，丙比乙多拿了4本，后来甲付给乙4元钱，丙应该付给乙多少元．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">2 * 1</gadget>
<output>2</output>

<result>2</result>