How to make the correct syntax?

Community
1 
<!DOCTYPE>
<html>
<head>
<title>QUIZ 01</title>
 <script>
var SCORE = 0
alert("Hello. What's your name?")
var name = prompt("Write your name")
alert("Nice to meet you, " + name + ".")
alert("I'm your system's assistant and I'm here to help you, " + name + ".")
alert("Before that, I need to make sure that you're not a robot.")
alert("It's an easy quick quiz")
alert("There will be 10 quick math questions for you!")
alert("You'll just need to answer them. But, the minimum of the score required is 5 true, 5 false.")
alert("Let's start!")
 var Answer1 = prompt("What's 3 + 3?")
		if (Answer1 == 6){
			SCORE =+ 1;
			alert("You're Correct!")
		    var Answer2 = prompt("What's 6 * 3?")
                    if(Answer2 == 18){
                          SCORE =+ 1;
                         alert("You're Correct!") 
                }   
		    else{
                         alert("WRONG!")
}
			
		}
		else{
			alert("wrong answer!")
			var Answer2 = prompt("What's 6 * 3?")
			
		}
		</script>
	</head>
	<body bgcolor="tomato">
	<h1 align="center"><b>TEST MATH-01</b></h1>
	<hr />
	<br />
	<br />
	<br />
	<div align="center";>
	    <script>
			document.write("Your Score is " + SCORE)
	    </script>
	</div>
	</body>
</html>
2

be aware of document.write behavior, it overwrites everything within body. Preferable avoid document.write

just put everything in a single script after the closing body tag:

</body>
<script>
   // all your JS code here
   // or use src attribute to link external JS file
</script>

this way, you ensure the DOM is loaded before script is executed.

to update SCORE do:

SCORE = SCORE + 1;

which can be shorten to:

SCORE += 1;

but then + comes before =, you got them in the wrong order.

also, align: center is heavily outdated.

All the alerts do generally not provide a pleasant UX (UX = user experience)

and this won’t stop an actually robot, the robot can just read the JS file and insert the answers. Client-side validation is nice to save requests to server, but always validate on back-end as well, otherwise your program is at serious risk

using consistent variable names is also recommended:

var SCORE
var name
var Answer1

you use 3 different styles for variable naming here (all uppercase, all lowercase and first letter uppercase). Check language spec for variable naming convention (although this are just recommendations, its unwise to not follow this convention)