'Two and a half' in the Bible

"They shall make an ark of acacia wood. Its length shall be two and a half cubits, its breadth a cubit and a half, and a cubit and a half its height.

You shall make a mercy seat of pure gold. Two and a half cubits shall be its length, and a cubit and a half its breadth.

Bezalel made the ark of acacia wood. Its length was two and a half cubits, and its breadth a cubit and a half, and a cubit and a half its height.

He made a mercy seat of pure gold. Its length was two and a half cubits, and a cubit and a half its breadth.