Answer:

ADDER

Answer	Crossword Clue
ADDER	Calculating snake?
ADDER	Harmless crawler
ADDER	Puff .. (venomous viper)

ADDER	Viper
ADDER	Milk snake
ADDER	First grader, math-wise
ADDER	Venomous viper
ADDER	Venomous snake
ADDER	Abacus user
ADDER	Common viper
ADDER	Hognose snake

ADDER	Snake
ADDER	Mathematical snake?
ADDER	Snake that counts?
ADDER	Abacus, at times?
ADDER	Serpent
ADDER	Deadly viper
ADDER	Snake that does sums?
ADDER	Snake with venom

ADDER	Slithering biter
ADDER	Reptile with a nasty bite
ADDER	European viper
ADDER	Columnist?
ADDER	Dangerous snake
ADDER	Summer
ADDER	Puff ..
ADDER	Calculator, at times

ADDER	One doing sums
ADDER	Snake with a puff variety
ADDER	Scary snake
ADDER	Kind of viper
ADDER	Poisonous snake
ADDER	Someone doing sums
ADDER	Sum kind of snake?
ADDER	Calculating person?

ADDER	Pocket calculator, e.g.
ADDER	Puff ... (dangerous snake)
ADDER	Dangerous slitherer
ADDER	Northern copperhead, for one
ADDER	Summer at the office

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.