Default number entering has messed up entering a number

Suddenly, if I enter a number, say, 5, it shows up as 0.05
To get 5 as 5, I have to enter 500
With ANY number I have to enter as the last two digits 00 to have the number shown correctly
This strangeness occurs with ANY new number
My Excel 2010 is doing this on new as well as ANY previous SS
It seems as if an Option has become changed, but if so, I cannot locate the Option control for this

Thanks

Solved!
Thank you
I kept missing the obvious