Related Clues:

• Go figure?
• Add later
• Do sumthing?
• Lengthen (with ''to'')
• Perform an operation?
• Write further
• Utter parenthetically
• Do sum math?
• Contribute (to)
• Put two and two together, say
• State further
• Chime in
• Work with a calculator, in a way
• Add as an afterthought
• Do some math