switch and math problem issues

I'm new to java and have a project that requires me to make a math quiz for an individual. its starts be having the individual choose between: addition(+), sub(-), mult(*), and div(/). from there there determine whether the user wants random integers of 1 or 2 decimal places.
Not sure how to use the switch in this case, please help.

Perhaps something like this.

Code :

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import java.util.Scanner;
 
public class ReadChar {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int decimal;
		switch (s.next().charAt(0)) {
			case '/':
			case '*':
				decimal = 2;
				break;
			default:
				decimal = 1;
				break;
		}
	}
}

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