Claire tried to subtract two polynomials. Her work is shown below:
$\begin{align}
&\phantom{=}(2x^2+2xy+5y^2)-(3x^2+4xy+6y^2)
\\\\
&=2x^2+2xy+5y^2-3x^2-4xy-6y^2&\text{Step }1
\\\\
&=(2+2)x^2y+(2+5)xy^2-(3+4)x^2y-(4+6)xy^2&\text{Step }2
\\\\
&=4x^2y+7xy^2-7x^2y-10xy^2&\text{Step }3
\end{align}$
**At which step did Claire make an error, if at all?**
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