What causes this:

Format a column as text
Enter into first cell 1257470
then next cell 12574700
then next cell 125747000
then next cell 1257470000
then next cell 12574700000
then next cell 125747000000, but it changes it to 1.25747E+11

What is going on with this???

Also, in a text cell, I enter

08-812000-02
then, go to edit replace and try to replace the '-' with nothing
but when it does, it changes the cell to 881200002 - it takes the
dashes, but it also takes off the leading zero???

WHY?

Any help with these two questions would be greatly appreciated.
ga

George Applegate