Write Ranges That Give Boundary Values One Answer

State which values belong to each range, then check the shared boundary before publishing the wording. A short range label is useful only when it preserves the rule your article is explaining.

First establish the allowed inputs and the meaning of each endpoint. Does the rule include the lower value, the upper value or both? If that information is missing from your source, obtain it before turning the range into an instruction.

The GOV.UK style guide, checked on October 8, 2026, recommends using “to” for ordinary numeric ranges in prose, with an exception for tables. That is its house convention. The word itself does not supply an inclusion rule for your example.

Start with the complete rule

Here is an original fictional paper-pack rule. The inputs are whole, nonnegative counts of sheets: zero is an allowed input to check, while a fractional count is outside this example's domain.

• Small: at least 1 and at most 4 sheets.

• Large: more than 4 and at most 8 sheets.

Those are the entire supplied category rules. They assign no category to 0 or 9 sheets. This does not establish what any real pack can hold.

Keeping the starting rule beside your wording gives the edit a reference. Your article brief can record both the reader's decision and the rule that supports it.

Repair the overlap at four

Suppose the draft says:

Small includes 1 through 4 sheets. Large includes 4 through 8 sheets.

Both ranges in that draft include 4. The Large sentence contradicts the supplied rule, which requires more than 4. Adding clearer punctuation would leave that error in place.

The corrected wording is:

Small covers 1 to 4 sheets, including both 1 and 4. Large covers 5 to 8 sheets, including both 5 and 8.

The lower Large value becomes 5 because the domain contains whole counts: the first allowed count greater than 4 is 5. If fractional values were allowed, that rewrite would need reconsidering; it would omit values between 4 and 5.

Do not decide inclusion from a dash, a layout convention or what seems likely. Compare the finished sentence with the actual rule.

Check the endpoints and their neighbors

These are the complete supplied test inputs and outcomes:

The lower and upper Small endpoints, 1 and 4, both belong to Small. The lower and upper Large endpoints, 5 and 8, both belong to Large. None of these valid inputs belongs to both categories.

Zero is below Small's minimum. Nine is above Large's maximum. Unassigned means neither supplied rule matches; it does not mean a suitable pack is impossible in the real world.

An unknown input has no supported category until its value is supplied. It must not become zero. The value 4.5 is known but outside the whole-count domain, so do not round it to 4 or 5 to make it fit.

Reuse the filled boundary check

Download the filled range boundary check CSV. It contains all eight completed rows, the domain decision, each category match, the outcome, a reason and an invented-teaching marker.

For valid inputs, the match columns contain true or false. The unknown row retains unknown; the invalid-domain row says not evaluated. Neither is an ordinary failed match: one lacks an input value, and the other fails the stated input rule before category matching.

To use the record for your own article, write the sourced rule and allowed inputs first. Replace the teaching rows with your endpoint and neighboring values, evaluate each category separately, and compare the final prose with those results. Where categories should be exclusive, investigate any row with two matches; where the rule should cover every allowed input, investigate an unassigned row.

Use the blog-writing guide to keep that explanation beside the reader's choice. The blogger's keyword guide helps choose the question the article should answer; the boundary check keeps its numeric answer faithful to the rule.