Related Clues:

• Do simple arithmetic
• Bring aboard
• Compute a total
• Do a little math
• Put in your two cents
• Foot up
• Do the math, in a way
• Throw back in
• Word in math class
• Tendency for one's mind to wander, for short
• Write a P.S.
• Obey the plus sign
• Sum more?
• With 42-Down, extensions
• Include, as a dash of cinnamon