# TT638D Four Function Targeted Generalization

Goal:
Fix TT638C dense failures before any dyadic/Mercy proof.

TT638C evidence:
- seen failed on uppercase canonical prompts for SUBTRACT, MULTIPLY, DIVIDE
- heldout failed on divide phrasing: `Create divide so it computes a over b.`

TT638D changes:
- balanced uppercase function-template coverage across ADD/SUBTRACT/MULTIPLY/DIVIDE
- explicit regression gate for TT638C failed prompts
- targeted divide `a over b` coverage
- fresh heldout prompts not used as train rows