Related Clues:

• I, for one
• The 3 or 5 in 3 + 5 = 8
• Number on either side of a +
• Either 2, in ''2+2''
• Part of a sum
• XVI, for one
• XII, for one
• One is one
• Inclusion in safer passwords
• X, e.g.
• Number next to a +
• 1, 2, 3, for instance
• Affable and sociable
• 1, 2, 3, say
• Symbol for number