NOTE: This usage is similar to de mo, but is more emphatic.
Sono mondai wa sensei de sae kotaerarenakatta.
Even the teacher couldn't answer the test question.
Sonna kantan na koto wa, kodomo de sae shitte imasu yo.
Even a child knows such a simple thing!
「A mere child would know something as simple as that.」
２．In the form sae ... -tara or sae ... -ba, implies that if something additional is (had been) done, a positive outcome will occur (would have occurred): "if only."
Mō go-fu sae attara, hikōki ni ma-ni-atta no ni...
If we had only five more minutes, we would have been on time for the flight.
Ken-chan wa atama ga ii-n desu kara, benkyō sae sureba ii daigakeu ni hairemasu yo.
Ken has a good head on his shoulders, so if he only studies, he'll be able to get into a good university.
Hope this helps!
°˖ ✧◝(○ ヮ ○)◜✧˖ °こゆうきあいはら°˖ ✧◝(○ ヮ ○)◜✧˖ °