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Question 4811: Natural Closed-Interval Cardinality

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0008-04811 · q-20261008-advance-20261011-r01-natural-number-0061

Original question and givens

N includes 0. lo=1, hi=10. Find |{n∈N: lo≤n≤hi}|, including endpoints.

  • G001 — N includes 0. lo=1, hi=10. Find |{n∈N: lo≤n≤hi}|, including endpoints.

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

N={0,1,2,...}

After

0 belongs;negative and nonintegral rational values do not

Conditions: none

This convention includes0 in N;distinguish membership,rational values,partial predecessors and closed intervals.

Step identifiers and dependencies

Rule: natural_zero_convention · Uses: G001

S002 · calculation

Before

inclusive interval endpoint difference := sub(10, 1)

After

inclusive interval endpoint difference = 9

Conditions: none

Subtract the lower endpoint from the upper endpoint.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

inclusive natural interval size := sum(9, 1)

After

inclusive natural interval size = 10

Conditions: none

The closed interval contains both endpoints,so add1.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

lo=1;hi=10

After

natural interval size=10

Conditions: none

If the upper endpoint is below the lower,the set is empty with size0;do not swap endpoints to manufacture another set.

Step identifiers and dependencies

Rule: ordered_natural_interval_boundary · Uses: G001, S003

Reverse checks

  • S004 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Recompute inclusive natural interval size with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute inclusive interval endpoint difference with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

10

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: 69eb349071af9b3aa3b5510361cec8a8e1cb1c42a3862794dabb2a409f77a97f
  • candidate record SHA-256: c945e9caff95db3403045153753e58505f3f4aa3cc4c284cdb6fca4a922bec36
  • semantic review receipt SHA-256: b6e05a3e8193a93db505dbf337528fca72e2e41528b1e92b698a3f0683d74289
  • question-first witness SHA-256: caa8693baf0b91acd09a20215d1aa6954ae513fc0b0814f26ac1c8c834b60d67
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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