Why does the US law sometimes mention numbers in both digits and letters?
<p>Why does the US law  sometimes mention numbers in both digits and letters?</p>
<p>E.g. <a href="https://www.govinfo.gov/content/pkg/CFR-2012-title8-vol1/pdf/CFR-2012-title8-vol1-sec316-5.pdf" rel="nofollow noreferrer">https://www.govinfo.gov/content/pkg/CFR-2012-title8-vol1/pdf/CFR-2012-title8-vol1-sec316-5.pdf</a>:</p>
<blockquote>
<p>Absences from the United States for
continuous periods of between <strong>six (6)</strong>
months and <strong>one (1)</strong> year during the periods for which continuous residence is
required under §316.2 (a)(3) and (a)(6)
shall disrupt the continuity of such
residence for purposes of this part unless the applicant can establish otherwise to the satisfaction of the Service.</p>
</blockquote>
<p>Typically people don't write the same info twice.</p>

<p>This is very common in all sorts of legal documents, not just the United States Code.  Another familiar example where this is seen is on <a href="https://www.huntington.com/Personal/checking/checks/how-to-write-a-check" rel="nofollow noreferrer">checks</a>.</p>
<p>It serves as a sort of &quot;redundancy check&quot;, to help catch errors where either the words or the numerals could have been incorrectly transcribed.  Of course, one could ask why similar redundancy isn't used to avoid errors in other contexts; there doesn't seem to be a good answer for this besides &quot;tradition&quot;.</p>
<p>Some people feel the practice is obsolete and should be abandoned, e.g. <a href="https://www.butlersnow.com/2020/04/five-5-reasons-to-stop-writing-numbers-like-this/" rel="nofollow noreferrer">https://www.butlersnow.com/2020/04/five-5-reasons-to-stop-writing-numbers-like-this/</a>.</p>

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