You learned about == and === earlier. In operators context:
// Strict equality (use this)
5 === 5 // true
5 === "5" // false (different types)
// Loose equality (avoid)
5 == "5" // true (coerces types)
Same for inequality:
5 !== 3 // true (strict, different values)
5 !== "5" // true (strict, different types)
5 != "5" // false (loose, coerces first)
Always use === and !== unless you have a specific reason not to.