| Answer | Crossword Clue |
|---|---|
| GIVEANDTAKE | Reciprocity. |
| TRADE | Reciprocity |
| ONEWAY | Without reciprocity |
| EACHOTHER | Words of reciprocity |
| EULER | Formulator of the quadratic reciprocity law |
| EULER | Formulator of the law of quadratic reciprocity |
| EULER | Discoverer of the law of quadratic reciprocity |
| GAUSS | He proved the Law of Quadratic Reciprocity |
