Only one at a time.
In the decimal system, 10 times.
There can only be one digit in each place value - before or after the decimal place.
To find how many significant digits are being displayed, you look down the place values until finding the first non-zero value. In this case, the first non-zero value is the 1 in the hundredths place. The next step is simply to count every value after that to see how many significant digits the number has been taken to. In this case there are 3.
infinite number of digits after the decimal point -- pi does not have a finite value.
In the decimal place value system, each digit is ten times bigger than the digit on its right