I've learnt mathematics in France with x for multiplication symbol and the comma for decimal separator. Returning to mathematics 30 years after, both tend to be replaced by the dot.
When I write 2.2 am I writing : 2 x 2 or 2,2 ?
2.2.5.3 = 2,2 x 5,3 ? I am a bit reluctant because I fear we can end to ugly things.
What are rules that have been taken to avoid confusions ?
The dot that stands for multiplication is usually placed higher like in $\cdot$ , the dot that represents the decimal is lower, like a period. Also in algebra many times the dot is omitted like in 2x or 2(x). To put a dot higher use \$\cdot\$ but this only works in platforms that support MathJax or LaTeX. This does work in math StackExchange so you can use it here.