Subtract b from the numerator of the fraction (29/43) and add b to the denominator, then the fraction after division is (2/3). Then b=how much.
将分数(29/43)的分子减去b，分母加b，则分数约分后是(2/3)．那么b=多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>