4.5 times of a number is 6.9 more than 5.7, find this number. (solution by equation)
一个数的4.5倍比5.7多6.9，求这个数．(用方程解)
<gadget id="calculator">6.9 + 5.7</gadget>
<output>12.6</output>

<gadget id="calculator">12.6 / 4.5</gadget>
<output>2.8</output>

<result>2.8</result>