TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Black widows mature in two to _ months.

SOLUTION: four

PROBLEM: R is an average of the color rendering ability of _ or more specific colors.

SOLUTION: eight

PROBLEM: Geologists now think the Earth is about _ and a half billion years old.

SOLUTION:
four