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  "body": "\n## Summary\n\nThe unit in the last place, or ulp, of a [[floating-point|RTKRSC3KPH]] number is the value of its last significant digit position.\nIt is the spacing between neighbouring floating-point numbers at that size.\nErrors of computed results are often stated in ulps.\nFor example, a result correctly rounded to nearest is within half an ulp of the exact value.\nThe ulp of $1$ is the [[machine epsilon|JA3QXVF2B8]].\n\n## Explanations\n\n### L1 human\n\nIf a ruler is marked in millimetres, one millimetre is the smallest step it can show.\nThe ulp is that smallest step for a floating-point number.\nIn decimal with three significant digits, the number $3.14$ has ulp $0.01$, while $314$ has ulp $1$.\nSo the ulp grows with the size of the number, which is why floating-point accuracy is relative and not absolute.\n",
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