instruction:
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.
question:
Hoatzin has typical foot with ____ toes forwards and one backwards.
answer:
three


question:
Airplanes still fly four to ____ times faster than zeppelins.
answer:
five


question:
Most people see the world through ____ types of visual-receptor cells.
answer:

four