Mom takes Xiao Ming to buy cloth. If she buys 2 meters, there is still 0.9 yuan left. If she buys 4 meters of the same cloth, there is still a difference of 1.2 yuan. Ask her how much money she brought.
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">2 * 1.05</gadget>
<output>2.1</output>

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

<result>3</result>