As many as there were before the number was read!
Billions are integers and so there will be no decimal points or digits after it.
The answer depends on how many decimal places are in the summands.
There are 27 of them.
You need to add up the number of digits to the right of the decimal to find the number of digits in the answer. If the first factor has 2 digits to the right of the decimal point and the second factor has 3, the final answer will have 5 digits to the right of the decimal point.
There can be only one.
It takes 7 digits.
A decimal is a way of representing a number in such a way that the place value of each digit is ten times that of the digit to its right. A decimal representation does not require a decimal point. It can have any number of digits: from one to infinitely many.
At least 1
5 digits will suffice.