Claude Sonnet 5 vs Grok 4.5 for bookkeeping

## Step 1 – Find the actual difference

Bank statement balance: **£8,412.55**
Cash book balance: **£8,376.55**

Difference = £8,412.55 − £8,376.55 = **£36.00**

The unpresented cheque and the outstanding lodgement are both £120.00, so they cancel out and are *not* the cause of the imbalance. The £36.00 has to be explained by something else.

## Step 2 – Spot the pattern in the receipts

Line up the cash book receipts against the bank credits:

| Cash book | Bank statement |
|---|---|
| 451.00 | 415.00 |
| 1,208.30 | 1,208.30 |
| 96.75 | 96.75 |…

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…