ER endings are:
Yo-o
Tu-es
El/Ella-e
Nosotros-Emos
Vosotros-eis
Ellos/ellas- en
Sudoku should mean that you can’t have the same ending in a row, column, or box
It’s 3 because they are telling you to put the table then someone else says “don’t put it” which is no la pongas
I believe this question should go under the "English" Section