| 1: | pred(s(x)) | → x | |
| 2: | minus(x,0) | → x | |
| 3: | minus(x,s(y)) | → pred(minus(x,y)) | |
| 4: | quot(0,s(y)) | → 0 | |
| 5: | quot(s(x),s(y)) | → s(quot(minus(x,y),s(y))) | |
| 6: | MINUS(x,s(y)) | → PRED(minus(x,y)) | |
| 7: | MINUS(x,s(y)) | → MINUS(x,y) | |
| 8: | QUOT(s(x),s(y)) | → QUOT(minus(x,y),s(y)) | |
| 9: | QUOT(s(x),s(y)) | → MINUS(x,y) | |