These symbols may have different terms in general speech than they have in the specific terminology of the programming language (C, C++, Java, etc.) that they are used in.
For example, the symbol "!" is normally called an "exclamation mark", but in the C, C++ and Java programming languages it's called "not". Likewise, "%" is usually called "percent", but in these programming languages it's called "mod" or "modulo".
Here are more from C and C++:
+ is "plus"
- is "minus"
+= is often called "plus equals"
*= is often called "times equals"
++ is often called "plus plus" or "increment"
You will find some of the answers you're looking for here:
https://en.wikipedia.org/wiki/Operators_in_C_and_C++