Related Clues:

• Compute, sometimes
• Write, as a P.S.
• Offer as a bonus
• Make a contribution
• Write in a postscript, e.g.
• Use a '+'
• Calculate the total
• Interrupt, as a news broadcast
• Cookbook directive
• Speak loudly
• ___ insult to injury
• Contribute, as to the conversation
• Do sum work
• Get a total
• Hyperactivity may be a sign of it, for short