Xiao Ming's mother goes to the store to buy soap. The unit prices of brand A soap and brand B soap are 6 yuan and 9 yuan respectively. If Xiao Ming’s mother brings all the money to buy brand A soap, she can buy 2 yuan more than buying all brand B soap, and there is no money left. So, how much money did Xiaoming's mother bring?
小明的妈妈去商店买肥皂，A牌肥皂和B牌肥皂的单价分别为6元和9元．小明妈妈带的钱全部买A牌肥皂比全部买B牌肥皂可多买2块，并且没有剩余的钱．那么，小明妈妈带了多少元钱．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/6) - (1/9)</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">2 / (1/18)</gadget>
<output>36</output>

<result>36</result>