\startbuffer
\the\dimexpr .4999pt : 2 \relax =.24994pt
\the\dimexpr .4999pt / 2 \relax =.24995pt
\the\dimexpr .4999pt ; 2 \relax =.00002pt
\scratchdimen.4999pt \divide \scratchdimen 2 \the\scratchdimen =.24994pt
\scratchdimen.4999pt \edivide\scratchdimen 2 \the\scratchdimen =.24995pt
\scratchdimen 4999pt \rdivide\scratchdimen 2 \the\scratchdimen =2500.0pt
\scratchdimen 5000pt \rdivide\scratchdimen 2 \the\scratchdimen =2500.0pt