It is known that a is 5 times of b, if a+b=150, then what is ab=.
已知a是b的5倍，如果a+b=150，则a-b=多少．
<gadget id="calculator">150 / 6</gadget>
<output>25</output>

<gadget id="calculator">5 * 25</gadget>
<output>125</output>

<gadget id="calculator">125 - 25</gadget>
<output>100</output>

<result>100</result>