Claude Opus 4.8 vs Grok 4.5 for bookkeeping

# Bank Reconciliation Error Analysis

## The Difference

£8,412.55 − £8,376.55 = **£36.00**

## Finding the Error

Comparing the cash book receipts with the bank credits:

| Cash book | Bank statement |
|-----------|----------------|
| £451.00 | £415.00 |
| £1,208.30 | £1,208.30 |
| £96.75 | £96.75 |
| £2,340.00 | £2,340.00 |
| £415.00 | £451.00 |
| £188.50 | £188.50 |

The figures **£451.00** and **£415.00** appear in *reversed order*. The digits 5 and 1 have been swapped: £4**51** became £4**15**.

## Kind of Error

This is a **transposition…

The balances differ by £36 (bank higher than cash book).  

This is a transposition error (digits reversed in one amount: 415.00 vs 451.00).  

Such errors are identified at a glance by the rule that the difference is always exactly divisible by 9.  

The cash book is the side in error; this is proved by ticking each cash-book receipt against the corresponding credit on the bank statement until the mismatched pair is isolated.  

Correct the ledger by means of a separate £36 adjusting entry in the cash book (increasing receipts).  
Do **not** a…