Related Clues:

• The 'x' in x³
• Two of eight, perhaps, heading for unrest in October after revolution
• Two, for eight
• Two, to eight, e.g
• 5, for 125
• 3, to 27
• 12, for 1728
• One is one's own man, no longer leading Englishmen behind block
• What turns 27 into 3, in math (2 words)