id = "entry-cents-add-exactly"
title = "Amounts are kept exactly: ten cents and twenty cents make thirty"
rule = "The books MUST keep every amount exactly and add exactly, so that no sum of cents differs from its true total by any amount, however small; rounding MUST NOT occur inside the books."
status = "AUTHORITY"
sources = [
  "IRS Form 1065 instructions: \"include cents when adding the amounts and round off only the total\" (docs/spec/sources/irs-partnerships.md)",
  "Pacioli, Summa (1494), ch. 36: the credits equal the debits, which no float sum guarantees (docs/spec/sources/pacioli-1494.md)",
]
tags = ["accrual", "book", "us", "entry", "exact"]

[setup]
currency = "USD"
fiscal_year_start = "01-01"
basis = "accrual"
rounding = "half-even"

[[setup.accounts]]
code = "1000"
name = "Cash"
type = "asset"

[[setup.accounts]]
code = "2000"
name = "Loan"
type = "liability"

[[setup.accounts]]
code = "3000"
name = "Capital"
type = "equity"

[[setup.accounts]]
code = "4000"
name = "Sales"
type = "revenue"
tax_category = "gross_receipts"

[[setup.accounts]]
code = "6000"
name = "Rent"
type = "expense"
tax_category = "rent_property"

# In binary floating point 0.1 + 0.2 is 0.30000000000000004. Two debits of
# 0.10 and 0.20 against one credit of 0.30 balance exactly.
[[events]]
date = "2026-01-05"
description = "Three small sales"
lines = [
  { account = "1000", side = "debit", amount = "0.10" },
  { account = "1000", side = "debit", amount = "0.20" },
  { account = "4000", side = "credit", amount = "0.30" },
]

[[events]]
date = "2026-01-06"
description = "A sale of a trillion and a cent"
lines = [
  { account = "1000", side = "debit", amount = "1000000000000.01" },
  { account = "4000", side = "credit", amount = "1000000000000.01" },
]

[[expect]]
query = "balances"
as_of = "2026-12-31"
[expect.values]
"1000" = "1000000000000.31"
"4000" = "1000000000000.31"