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: Igneous rock occurs in ____ ways .

SOLUTION: two

PROBLEM: Fire occurs any time ____ elements are present - fuel, heat, oxygen and the chemical chain reaction.

SOLUTION: four

PROBLEM: Most Atlantic mackerel are sexually mature by the age of ____ years.

SOLUTION:
three