Recognising When A Number Has Been Rounded Misleadingly
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Rounding a figure makes it noticeably easier and quicker to read at a glance, but repeated rounding carried out across several successive retellings can gradually drift a number meaningfully further away from its original, true value, especially when each individual version happens to round in the same consistent direction rather than genuinely to the nearest figure each time.
Percentage changes are particularly prone to this exact kind of drift, since a rounded starting figure combined together with a separately rounded ending figure can easily produce a percentage change that looks considerably more dramatic overall than the actual underlying data genuinely supports upon close inspection later.
Tracing a striking rounded figure carefully back to its original, unrounded source, wherever that happens to be practical to do, is a genuinely useful check whenever a number appears to be doing significant persuasive work within a much broader claim being made to an audience somewhere.