Related Clues:

• Includes in the mix
• Offers as an afterthought
• Puts two and two together, say
• U-turn from subtracts
• Stirs in, say
• Finds sum thing
• Re-checks the check
• Calculates sums
• Gets sum?
• Moves abacus beads
• Is calculating?
• Starts to stock
• Does sum math
• Makes sense, with ''up''
• Is mathematical