Calculate Number with operator

Main.java

import java.text.DecimalFormat;
import java.util.Scanner;

public class Main {

    private static Scanner scanner;

    public static void main(String[] args) {
        init();
        doSomeThing();
    }

    private static void init() {
        scanner = new Scanner(System.in);
    }

    private static void doSomeThing() {
        String number = scanner.nextLine();
        cutNumber(number);
    }

    private static void cutNumber(String number) {
        int operator = checkOperatorPosition(number);
        int numberA = Integer.parseInt(number.substring(0, operator));
        int numberB = Integer.parseInt(number.substring(operator + 1));
        double total = calculate(number, numberA, numberB);
        DecimalFormat dc = new DecimalFormat("0.00");
        System.out.println(dc.format(total));
    }

    private static int checkOperatorPosition(String number) {
        if (number.contains("+")) {
            return number.indexOf("+");
        } else if (number.contains("-")) {
            return number.indexOf("-");
        } else if (number.contains("*")) {
            return number.indexOf("*");
        } else if (number.contains("/")) {
            return number.indexOf("/");
        } else {
            return number.indexOf("%");
        }
    }

    private static String checkOperator(String number) {
        if (number.contains("+")) {
            return "+";
        } else if (number.contains("-")) {
            return "-";
        } else if (number.contains("*")) {
            return "*";
        } else if (number.contains("/")) {
            return "/";
        } else {
            return "%";
        }
    }


    private static double calculate(String number, int numberA, int numberB) {

        double a = (double) numberA;
        double b = (double) numberB;

        double sum = 0;

        switch (checkOperator(number)) {
            case "+":
                sum = a + b;
                break;
            case "-":
                sum = a - b;
                break;
            case "*":
                sum = a * b;
                break;
            case "/":
                sum = a / b;
                break;
            case "%":
                sum = a % b;
                break;
            default:
                break;
        }
        return sum;
    }


}