51. 51. 51. 51.
Seventeen, with a remainder.
Currently (Sept 2014), the number of digits is 10 trillion (and fifty).
27 threes are in 81
There are four threes in a standard deck of cards.
51. 51. 51. 51.
Not counting the three in the ones place, there are 100229.
100230, which includes the first one to the left of the decimal point.
Fifty threes are in 150.
We only use 10 digits (0 through 9), so I would say, there is one of them.
There are 100229 threes and 100106 nines. A table of all the digit frequencies can be found at http://www.super-computing.org/pi-decimal_current.html
Not counting the 3 in the ones place, there are 100229 threes and 100106 nines.
About 100,000 of each.
Seventeen, with a remainder.
Fifteen. 3, 13, 23, 30, 31, 32, 33*, 34, 35, 36, 37, 38, 39, 43. Note 33 has two threes.
Currently (Sept 2014), the number of digits is 10 trillion (and fifty).
27 threes are in 81