The phrase "added by mistake" is correct and usable in written English.
It can be used when referring to something that was unintentionally included or inserted into a document, message, or situation.
Example: "The extra paragraph was added by mistake, and we need to remove it before finalizing the report."
Alternatives: "included unintentionally" or "inserted accidentally."
"On first examination I probably wrote down cloth," the witness said, adding, "by mistake I probably overwrote it".
Subsection (d) is substituted for the last 2 sentences (added twice by mistake) in paragraphs (1) and (2) and for the last sentence in paragraphs (3), (4), and (7)(C) of section 206(b) of the National Driver Register Act of 1982 (Public Law 97 364, 96 Stat. 1744) for clarity and to avoid repeating the provision unnecessarily.
The authors proposed that E. coli K-12 WaaO cannot work unless the branched galactose added by WaaB is present and that the HexIII glycosyltransferase (WaaR in E. coli K-12) might mistake the GlcI added by WaaG for GlcII added by WaaO and inefficiently add a terminal glucose.
"The figures involved would be so large – I thought someone may have added some zeros by mistake; £12bn is an absolutely huge sum.
He added: "When I first wrote to Vince Cable [the Business Secretary] I had no idea that the figures involved would be so large – I thought someone may have added some zeros by mistake; £12bn is an absolutely huge sum.
The hospital, he added, "was hit by mistake as a result of Medicins Sans Frontieres providing wrong coordinates".
The statement added that the mistake was discovered by a subsea robot within 24 hours.
I'm going to write that again so no-one thinks I've added an extra nought by mistake.
Look at the image carefully - you may not have seen it how you thought it was like, and because of that, the image might have been removed or added into the article by mistake.
