My mother took Xiaoming to buy cloth. If I bought 2 meters, there was still 0.9 yuan left. If I bought 4 meters of the same cloth, there was still a difference of 1.2 yuan. How much did my mother bring?
妈妈带小明买布，如果买2米还剩0.9元，如果买4米同样的布，还差1.2元，问妈妈带了多少元钱？
<gadget id="calculator">0.9 + 1.2</gadget>
<output>2.1</output>

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

<gadget id="calculator">2.1 / 2</gadget>
<output>1.05</output>

<gadget id="calculator">1.05 * 2</gadget>
<output>2.1</output>

<gadget id="calculator">2.1 + 0.9</gadget>
<output>3</output>

<result>3</result>