By default a value is rounded up if the next digit is bigger than or equal to 5. For example 1.245 will be rounded to 1.25 and 1.243 will be rounded to 1.24. In order to change that behavior you would need to use custom logic. I can suggest handling the change event and round the entered value manually.
The dojo example below illustrates the approach:
Give it a try and let me know how it works for you.