There was this sentence from iKnow:
私は左右で足の大きさは違います。
The translation was: My left and right feet are of different sizes.
I don’t understand the usage of で in this sentence. In my own literal translation, its “In my left and right, the size of my foot are different.” But shouldn’t it be 左右の足 instead (as foot’s left and right)???
I’m sorry for the noob question 
Isn’t で used here because your 足 are at your 左右?
Left and right <— at foot’s size is different. Arrow indicating where foot is “at.” I could be off, but that’s what it looks like to me.
Maybe it’s the “indicates location of action” meaning 
I also saw that sentence and thought for a bit “huh, this is weird. better remember this for future reference”.
That was the way I read it.
My literal reading: As for me, on the left and right, foot size differs.
Maybe it would be better to think of the translation as something more remixed like “The size of my feet are different [between] the left and right [sides]” to maybe to make it more clear as the purpose of the で in the sentence?
This makes a lot more sense, thank you!
Yeah. You’re welcome. It comes across maybe as a less natural English sentence, but (assuming I’m not just wildly off in translating) at least to me helps convey the Japanese grammar in a more straightforward way.
One thing I dislike with some teaching materials is they focus too much on writing the most natural sounding sentence (which is great if I’m reading a translated novel) to the detriment of obscuring the Japanese grammar. It’s why I like materials that give a more literal, if less natural sounding, translation along with the more prettified English.
I agree. I’ve just began watching Cure Dolly in youtube, and her explanation for the particle usage and grammar is probably the “most Japanese” among all those I’ve read before. Especially the が and は. Her literal translations make the most sense, even though it really sounds awkward when told in English.
Literal translations usually are.