TASK DEFINITION: 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.
PROBLEM: Gorillas are sexually mature at ____ to nine years of age.

SOLUTION: six

PROBLEM: Primates have ____ digits on their forelimbs.

SOLUTION: five

PROBLEM: Some steam locomotives utilize ____ sets of engines.

SOLUTION:
three