Japanese by Example
Learning through examples in manga

So, which is which with それで

あしたは土曜日 » Volume 春・夏 » Page 90

Mina tells Sanae that if you clasp your hands together, you can know whether you were a boy or a girl in a past life. When Mina interlocks her fingers, her left thumb is on top. For Sanae, it’s her right thumb. In the past, one was a boy, and the other was a girl.

サナエ:
それで、どっちがどっちなの?」
"So, which is which?"