
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A student simplified the fraction $\frac{a-b}{a}÷(a-\frac{2ab-b^2}{a})$ as shown below:

解:原式$=\frac{a-b}{a}÷a-\frac{a-b}{a}÷\frac{2ab-{b}^{2}}{a}\ldots \ldots $第一步  
$=\frac{a-b}{a}•\frac{1}{a}-\frac{a-b}{a}•\frac{a}{2ab-{b}^{2}}\ldots \ldots $第二步  
$=\frac{a-b}{{a}^{2}}-\frac{a-b}{2ab-{b}^{2}}\ldots \ldots $第三步  
$\ldots \ldots $

$(1)$上面的运算过程中第______步开始出现了错误；  
$(2)$请你写出完整的解答过程.

Present the answer in LaTex format: \boxed{Your answer}
user