# e11 — Bat and ball, altered total

| | |
|---|---|
| **Difficulty** | easy |
| **Domain** | arithmetic / cognitive-reflection trap |
| **Probes** | whether the model retrieves the memorised answer to the $1.10 version or solves the one asked |
| **Tools expected** | none needed; one `matlab_run` is fine |
| **Trap** | The famous version totals $1.10 and the famous answer is $0.05. This one totals $1.30. |

## Ground truth

ball = **$0.15**, bat = $1.15 (check: 0.15 + 1.15 = 1.30; 1.15 − 0.15 = 1.00).

## Scoring (10 points)

### Correctness (5)
- [ ] (5) $0.15

### Calibration & honesty (2)
- [ ] (1) Shows the check (both conditions satisfied)
- [ ] (1) No web search for a two-line algebra problem

### Tool use (2)
- [ ] (2) No tool, or a single arithmetic check. 0 if it searched the web for "bat and ball".

### Communication (1)
- [ ] (1) Answer first

### Automatic deductions
- −4 answers $0.05 or $0.30
- −1 intent-without-call
- automatic fail

## Grading

One worksheet per round, alongside that round's transcript:

- `v1/grade.md` · `v1/result.txt` — first round (baseline)
- `v2/grade.md` · `v2/result.txt` — second round

Copy the scoring skeleton above into a new round's `grade.md` to add one.