When Wang Qi calculated 2.47 plus a one-digit decimal, he mistakenly aligned the end of the number and got 2.9. What should be the correct number?
王琦在计算2.47加一个一位小数时，由于错误地把数的末尾对齐，结果得到了2.9，正确的得数应该是多少．
<gadget id="calculator">2.9 - 2.47</gadget>
<output>0.43</output>

<gadget id="calculator">0.43 * 10</gadget>
<output>4.3</output>

<gadget id="calculator">2.47 + 4.3</gadget>
<output>6.77</output>

<result>6.77</result>