Understand how the modulus operator works in simple cases (i.e., with positive operands).
Understand how logical expressions work. What evaluates to "true" or "false"? What is the numerical value of an expression that evaluates to "true" or "false"?
What happens if you try to pass a value of the wrong type in a function call?
Understand and be able to use the ternary operator.
You will need to be familiar with the binary representation of numbers. (You can reasonably be expected to handle numbers from 0 to 256.)
Understand the use of bitwise operators.
Understand the basics of switch statements, and how they work, including the use of the keywords "case" and "default".
Understand when the use of the "break" keyword in a switch statement is required, when it can useful to omit it, and when it's not required but probably a good idea.
The three expressions separated by semicolons in a for loop are allowed to be empty. What happens if the first, second, or last of these is empty?
Understand the effect of the keywords "break" and "continue" in loops.