Using 1/3 as an example,

```
>>> 1./3
0.3333333333333333
>>> print "%.50f" % (1./3)
0.33333333333333331482961625624739099293947219848633
>>> print "%.50f" % (10./3)
3.33333333333333348136306995002087205648422241210938
>>> print "%.50f" % (100./3)
33.33333333333333570180911920033395290374755859375000
```

which seems to mean real (at least default) decimal precision is limited to "double", 16 digit precision (with rounding error). Is there a way to increase the real precision, preferably as the default?

For instance, UBasic uses a "Words for fractionals", f, "Point(f)" system, where Point(f) sets the decimal display precision, .1^int(ln(65536^73)/ln(10)), with the last few digits usually garbage.

Using "90*(pi/180)*180/pi" as an example to highlight the rounding error (4 = UBasic's f default value):

```
Point(2)=.1^09: 89.999999306
Point(3)=.1^14: 89.9999999999944
Point(4)=.1^19: 89.9999999999999998772
Point(5)=.1^24: 89.999999999999999999999217
Point(7)=.1^33: 89.999999999999999999999999999999823
Point(10)=.1^48: 89.999999999999999999999999999999999999999999997686
Point(11)=.1^52: 89.9999999999999999999999999999999999999999999999999632
```

If not in the core program, is there a higher decimal precision module that can be added?

The decimal module provides support for decimal floating point arithmetic. Python has a complete documentation on it please look at https://docs.python.org/2/library/decimal.html

If you are looking something different please comment :)