Related Clues:

• Do an operation where you carry the one, say
• ___ Friend (Facebook option)
• Supplement, with "to"
• Sum up; say further
• Violent Femmes "___ It Up"
• Violent Femmes: "___ It Up"
• System of a Down song off "Steal This Album!"
• System of a Down song about math?
• Contribute a member
• Gain a section
• Ritalin target, for short
• Use the minus button
• Do a bit of math
• Do a KenKen operation
• Inject