# C942 — One carry exchange

## Question

Why do the two cumulative branches differ by 990?

## Inputs

```json
{
  "branches": [
    [
      11,
      15,
      10
    ],
    [
      12,
      5,
      10
    ]
  ]
}
```

## Sources

```json
[
  "C940",
  "C941"
]
```

## Opened utc

2026-09-28T03:42:35.051400+00:00

## Results

```json
{
  "column_exchange": [
    1,
    -10,
    0
  ],
  "original_change": 0,
  "reversed_change": -990
}
```

## Finding

A hundreds increment and ten tens decrement preserves the original sum but moves its reversed measurement by −990.

## Reassessment

Test the full linear kernel to distinguish aggregate recovery from component recovery.

## Checks

```json
{
  "same_original": true,
  "branch_gap": true
}
```

## Closed utc

2026-09-28T03:42:35.051584+00:00

## Record provenance

Exact record hash: `a264518bc82fc00891a204d9acd4cf1d93ad884b84261affff42a864403eb286`

Source journal: `Research_Cycles/C0932_C1131/journal.json`