The latest release of MathPad is version 3.04. It requires OS-X v10.6 or better. Previous versions are available for download here.
Detailed version history.
[MathPad_265.zip] (616K) -- MathPad 2.6.5 full distribution.
[MathPad_265.sit] (548K) -- The .sit archive and .zip archive contain the same files. The .zip archive may not expand properly on older systems so OS-9 users may need the .sit archive.
Version 2.6 XFuns
Version 2.6.4 is superseded by 2.6.5 but is still available.
[MathPad_264.sit] (548K) -- MathPad 2.6.4 full distribution
Version 2.6.3 is superseded by 2.6.4 but is still available.
[MathPad-263.bin] (495K) -- MathPad 2.6.3 full distribution
Version 2.5.2 may be more appropriate if your system is a bit older. The distribution contains both a powerPC and a 68K application that should run on any mac with system 7 or better and a 68020 processor or better.
[MathPad-252.bin] (577K) -- MathPad 2.5.2 full distribution
This version is essentially the same but is slightly larger and slower than the standard 2.4.7. Documentation and examples can be found with the MathPad 2.4.7 full distribution.
[MathPad-247S.bin] (77K) -- MathPad 2.4.7S application only.
[MathPad235.bin] (132K) -- MathPad 2.3.5 full distribution.
If you are trying to run system 4, it just might be time to consider an upgrade before your 400K floppy drive wears out.