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R0070-35787 · q-20260914-variable-expression-evaluation-0007
In N, let x=18. Evaluate the algebraic expression x+2; this is an expression, not an equation.
G001 — In N, let x=18. Evaluate the algebraic expression x+2; this is an expression, not an equation.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.
Before
source roles = [qf-variable-expression-evaluation, [assigned_value, constant, expression_form, number_system, operator, variable]]
After
derived = [variable, null, null]
Conditions: none
Use THIS bank’s actual fields,operation/domain and types.BASE retains permissible extra metadata.Do not import LDL SAFE/set limits or a different bank’s deduplication rules.
Rule: R70_SOURCE_bank_specific_interface · Uses: G001
Before
source roles = [18, 2]
After
derived = [x := 18, x + 2]
Conditions: none
Substitute the GIVEN assignment into x+constant.The variable already has a value;this is not solving an unknown equation or proving a universal identity from one example.
Rule: Variable_GIVEN_assignment_not_equation_solving · Uses: G001, S001
Before
Variable ORIGINAL assignment plus constant := sum(18, 2)
After
Variable ORIGINAL assignment plus constant = 20
Conditions: none
This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.
Rule: exact_rational_arithmetic · Uses: G001, S002
Before
source roles = [18, 2]
After
derived = [20]
Conditions: none
Both terms lie in N,so their exact sum remains in N.Retain the NUMBER type of the numerical answer.
Rule: Variable_substituted_nonnegative_sum · Uses: G001, S003
S004 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.S003 · premise_and_result_audit — Recompute Variable ORIGINAL assignment plus constant with exact rational arithmetic, not rounded decimals.S002 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.S001 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.20
The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.
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.
input commit: 0f7be61e2c22317a4075561dc822c87d881a50dboriginal question SHA-256: 5829a777f9fa38f736fbd8126b1a647a5c3f59b9486657ea043230324ffc4715candidate record SHA-256: f1218c5275137f761330e815d9a1075ff6a5a9f9c3fbf2a4400e6a18bde95cfesemantic review receipt SHA-256: 9820ac6529139bd53d516c8bfdfdd41184b0cd52dad69fa433344010db37af80question-first witness SHA-256: c9c939762bbd4d3ea3403084c8e95541dc2c7e56eb82fc74eaba8c80a4517dabLean: NOT_RUN · human review: NOT_PERFORMED