Noah took a pair of each unclean animal. In what number did he take each kind of clean animal?

Answer: By sevens

God told Noah to take clean animals by sevens (BSB: "seven pairs") but only a pair, male and female, of each unclean kind.

“You are to take with you seven pairs of every kind of clean animal, a male and its mate; a pair of every kind of unclean animal, a male and its mate;”— Genesis 7:2 (BSB)