I use Python REPL for simpler arithmetic operations

The perldl shell, which is part of PDL, can be handy for the same thing:

C:\>perldl
perlDL shell v1.357
 PDL comes with ABSOLUTELY NO WARRANTY. For details, see the file
 'COPYING' in the PDL distribution. This is free software and you
 are welcome to redistribute it under certain conditions, see
 the same file for details.
ReadLines, NiceSlice, MultiLines  enabled
Reading PDL/default.pdl...
Found docs database C:/_64/strawberry-5.26.1-PDL/perl/vendor/lib/PDL/p
+dldoc.db
Type 'help' for online help
Type 'demo' for online demos
Loaded PDL v2.018 (supports bad values)

Note: AutoLoader not enabled ('use PDL::AutoLoader' recommended)

pdl> p sqrt(9**5)
243

pdl>
[download]

And no need to explicitly import anything !

Cheers,
Rob