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R0058-29587 · q-20261013-advance-20261022-r02-present-value-discounting-0012
Use a fixed rate i=-1/20 per declared period, with 1+i>0, fixed period conventions and no cash flows, fees, taxes or rounding. Amounts are nonnegative exact rationals. Use exact rationals, normalize denominator signs, reduce fractions and omit /1 for integer outputs. This is not investment advice, a quote or a market forecast. future amount=133/3. Give (future amount,rate,1+rate,present value=future/(1+rate)). A permitted negative rate may make present value exceed future value.
G001 — Use a fixed rate i=-1/20 per declared period, with 1+i>0, fixed period conventions and no cash flows, fees, taxes or rounding. Amounts are nonnegative exact rationals. Use exact rationals, normalize denominator signs, reduce fractions and omit /1 for integer outputs. This is not investment advice, a quote or a market forecast. future amount=133/3. Give (future amount,rate,1+rate,present value=future/(1+rate)). A permitted negative rate may make present value exceed future value.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-str22-presentvalue-one-period-discount, presentvalue-one-period-discount]
After
derived = [[future, rate, factor, present]]
Conditions: none
Follow THIS bank exact keys,domain/frame,operation and answer role.STR22/App20 tuples differ from legacy scalars;retain or omit/1 by the ORIGINAL contract,not a generic visual convention.
Rule: R58_EXACT_source_interface_and_answer_ROLE · Uses: G001
Before
source roles = [Present value rate, [-1, 20]]
After
derived = [-1/20]
Conditions: none
Check BOTH raw pair components within1e6 and nonzero denominator BEFORE sign/gcd normalization.This STR22 profile must not be imposed on legacy SAFE/BigInt tasks.
Rule: STR22_input_RAW_pair1e6_before_sign_gcd_normalization · Uses: G001, S001
Before
Present value ORIGINAL positive accumulation factor := sum(1, -1/20)
After
Present value ORIGINAL positive accumulation factor = 19/20
Conditions: none
Substitute exact ORIGINAL operands.Additional teaching algebra does not inherit raw-input caps;only declared SOURCE rational operations apply their own profile.
Rule: exact_rational_arithmetic · Uses: G001, S002
Before
source roles = [Present value ORIGINAL positive accumulation factor, sum, [1, -1/20]]
After
derived = [[1], [19, 20], 19/20]
Conditions: none
SOURCE addition first uses denominator gcd,and multiplication cross-cancels.Check BOTH resulting raw components within1e6 BEFORE final reduction.Division qualifies the nonzero reciprocal.Do not substitute another bank profile or loosen a source hold.
Rule: STR22_SOURCE_gcd_crosscancel_THEN_raw1e6_BEFORE_final_reduction · Uses: G001, S003
Before
source roles = [-1/20, 19/20]
After
derived = [Yes]
Conditions: none
Use the SAME fixed per-period rate/period convention without cash flows,fees,taxes or rounding.Require1+rate>0;the rate may be negative.This is not a market forecast or investment advice.
Rule: Present_value_FIXED_model_same_rate_period_NOcashflows · Uses: G001, S004
Before
source roles = [Present value future, [133, 3]]
After
derived = [133/3]
Conditions: none
Check BOTH raw pair components within1e6 and nonzero denominator BEFORE sign/gcd normalization.This STR22 profile must not be imposed on legacy SAFE/BigInt tasks.
Rule: STR22_input_RAW_pair1e6_before_sign_gcd_normalization · Uses: G001, S005
Before
Present value ORIGINAL one-period future over factor := div(133/3, 19/20)
After
Present value ORIGINAL one-period future over factor = 140/3
Conditions: none
Substitute exact ORIGINAL operands.Additional teaching algebra does not inherit raw-input caps;only declared SOURCE rational operations apply their own profile.
Rule: exact_rational_arithmetic · Uses: G001, S006
Before
source roles = [Present value ORIGINAL one-period future over factor, div, [133/3, 19/20]]
After
derived = [[19, 1], [140, 3], 140/3]
Conditions: none
SOURCE addition first uses denominator gcd,and multiplication cross-cancels.Check BOTH resulting raw components within1e6 BEFORE final reduction.Division qualifies the nonzero reciprocal.Do not substitute another bank profile or loosen a source hold.
Rule: STR22_SOURCE_gcd_crosscancel_THEN_raw1e6_BEFORE_final_reduction · Uses: G001, S007
Before
source roles = [133/3, -1/20, 19/20]
After
derived = [140/3]
Conditions: none
From future=present*(1+rate) and positive factor,divide by the SAME factor to recover present,not multiply again.A negative rate may make present exceed future.
Rule: Present_value_ONE_period_inverse_of_same_forward_factor · Uses: G001, S008
S009 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S008 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S007 · premise_and_result_audit — Recompute Present value ORIGINAL one-period future over factor with exact rational arithmetic, not rounded decimals.S006 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S005 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S004 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S003 · premise_and_result_audit — Recompute Present value ORIGINAL positive accumulation factor with exact rational arithmetic, not rounded decimals.S002 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.S001 · premise_and_result_audit — Reverse-check EACH original datum,index,direction,representative and premise,not only the answer.Exact candidate checking,independent review,formal proof and publication clearance remain separate.(133/3, -1/20, 19/20, 140/3)
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: 855eee33140472f7e4dd9609571cefa193926dce3871ca1e3a75ea84e3cd95e0candidate record SHA-256: d114dadbdab3b8aa793004d0cd4ec44fc9ed54146259514868743a2e4edce93dsemantic review receipt SHA-256: 66bbb31c5fe644576dfd47ac71ca9e367fc23b948eac8e3eb648d96dadea05dfquestion-first witness SHA-256: b1e4fbdbca8d0ac3581e2f26466374d870f3c8498fab7cf6873feca5bbec44e7Lean: NOT_RUN · human review: NOT_PERFORMED