---
title: "Numbers Held Inexactly on the ZX81 (Part 5)"
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excerpt: "Fifth and final part of the series, covering FOR-NEXT loop counter behavior with non-integral step values. Explains why floating-point imprecision requires slightly overstating loop limits and rounding with INT(N+.5). Also notes a subtraction quirk in the ZX81's ROM and its source."
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volume: "3"
issue: "7"
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    title: "Syntax/Syntax ZX80 v3 n7"
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pages: "14"
pubdate: "July 1982"
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---

# Numbers Held Inexactly on the ZX81 (Part 5)

Fifth and final part of the series, covering FOR-NEXT loop counter behavior with non-integral step values. Explains why floating-point imprecision requires slightly overstating loop limits and rounding with INT(N+.5). Also notes a subtraction quirk in the ZX81’s ROM and its source.