Write numerals for each of the italicized number word names found in these examples. Earth’s moon is (a) two million, one hundred fifty-five thousand, one hundred twenty miles across. The closest distance between Earth and the moon is (b) two hundred twenty-five million, sixty thousand miles. The farthest distance between them is (c) two hundred fifty-one million, seven hundred twenty thousand miles.

It is not really difficult writing numerals if you have only their word names - just make sure you know how many numbers a million consists of, a thousand, etc.
A. two million, one hundred fifty-five thousand, one hundred twenty =
2,155,120
B. two hundred twenty-five million, sixty thousand =
225,060,000
C. two hundred fifty-one million, seven hundred twenty thousand =
251,720,000