* "One thousandth" (this is the most accurate and formal way)
* "Point one zero zero zero" (this is more common in technical contexts)
* "Point one" (this is informal and assumes the zeros after the decimal are not significant)
The spelling of 0.1000 would be:
* zero point one zero zero zero
* point one (informally)
It's important to note that the zeros after the decimal in 0.1000 are significant. This means they contribute to the accuracy of the number. However, in informal contexts, the zeros might be omitted.