Related Clues:

• What it takes?
• One and one
• Number to tango
• Phone's ABC
• Aces, perhaps
• Only even prime number
• Pencil number
• One and the same?
• What 35-Down may be for?
• ''___ can play that game''
• ''Terrible'' age
• Hand holding?
• Four and four, say
• A brace of
• A solid-colored billiard ball