Related Clues:

• Certain viper
• One doing sums
• Snake or calculating person
• Sum kind of snake?
• Calculator, at times
• Snake or CPA
• Abacus, e.g.
• Calculator user
• Hognose snake: puff ___
• Viper, and a clue to this puzzle's theme
• Snake with a puff variety
• Sum seeker
• Rattlesnake's cousin
• Small snake
• Snake that does sums?