| 1: | minus(X,0) | → X | |
| 2: | minus(s(X),s(Y)) | → p(minus(X,Y)) | |
| 3: | p(s(X)) | → X | |
| 4: | div(0,s(Y)) | → 0 | |
| 5: | div(s(X),s(Y)) | → s(div(minus(X,Y),s(Y))) | |
| 6: | MINUS(s(X),s(Y)) | → P(minus(X,Y)) | |
| 7: | MINUS(s(X),s(Y)) | → MINUS(X,Y) | |
| 8: | DIV(s(X),s(Y)) | → DIV(minus(X,Y),s(Y)) | |
| 9: | DIV(s(X),s(Y)) | → MINUS(X,Y) | |