TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Many Asian countries deny entry to travelers whose passports are valid for less than _ months.

SOLUTION: six

PROBLEM: Comets are a bit like giant dirty ice-balls with diameters between _ and fifty kilometres.

SOLUTION: five

PROBLEM: Vitamins are classified into _ groups.

SOLUTION:
two