That would be four billion and six or 4,000,000,006.
2.46
2,010,280,113.55
74749
You write it as 4.
8.048 is the whole number, so it goes in the ones column. 4 hundredths is the second digit after the decimal.
.1111
4,448
8,204,528,204
It is 9326.
In word forms, you can write it as 20 billion dollars, twenty billion dollars, $20 billion. Or you can write it as $20,000,000,000. There are at least 4 ways to write it, and probably more.
2.004
1, 2, 3, 4 etc. up to 1,000,000,000