But if it wasn't for Mr. Euler -- who wrote almost 70 volumes of mathematics and had 13 children, who he apparently would dandle on his knee while he was writing -- if it wasn't for Mr. Euler, there wouldn't perhaps be these invariants.
Mas se não fosse o Sr. Euler — que escreveu quase 70 volumes de matemática, teve 13 filhos que, segundo parece, brincavam nos joelhos dele,  enquanto ele escrevia — se não fosse o Sr. Euler,  talvez não houvesse estas invariantes.