Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Hamsters can live to be ____ to four years old.
three

Kayak paddles have ____ blades, canoe paddles have one.
two

Salmonids use ____ forms of cover, overhead and submerged.

two