Your question has nothing to do with "converting" numbers. Your question pertains to how numeric values are presented on the display.
It is common to confuse how numeric values are stored with how they are presented. Just copy and paste the following sequence of commands in MATLAB's Command Window and examine the output. Of course, you should also have a look at the documentation for the format (link) command.
r = [0.12345, 6789.0];
format
r
format short
r
format shorte
r
format shortg
r
format long
r
format longe
r
format longg
r
Output:
r =
1.0e+03 *
0.0001 6.7890
r =
1.0e+03 *
0.0001 6.7890
r =
1.2345e-01 6.7890e+03
r =
0.12345 6789
r =
1.0e+03 *
0.000123450000000 6.789000000000000
r =
1.234500000000000e-01 6.789000000000000e+03
r =
0.12345 6789
