instruction:
In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
question:
New species are believed to arrive in the Mediterranean at the rate of _ to five annually.
answer:
four


question:
Pharmacists dispense nearly _ billion prescriptions a year.
answer:
three


question:
Elephants also have four molars, one on the top and _ on the bottom on both sides of the mouth.
answer:

one