Related Clues:

• Top gymnastics rating
• Rating some might give 1-Across
• Power base?
• Top number in the Mohs scale
• *The floor
• Common face card value
• A bit less than a dozen
• No Clue
• One of Lincoln's sons
• Basis of the decimal system
• Famous Downing Street address
• David Cameron's house number
• High end of many a scale
• "Speed" of many bikes
• Scientific notation figure