Validate mathematical expressions using regular expression?

Question

I want to validate mathematical expressions using regular expression. The mathematical expression can be this

1. It can be blank means nothing is entered

Answer 1

This is java regex, but this is only if not have any braces

[+\-]?(([0-9]+\.[0-9]+)|([0-9]+\.?)|(\.?[0-9]+))([+\-/*](([0-9]+\.[0-9]+)|([0-9]+\.?)|(\.?[0-9]+)))*

Also this with braces in java code
In this case I raplace (..) to number (..), should matches without brace pattern

    //  without brace pattern
    static Pattern numberPattern = Pattern.compile("[+\\-]?(([0-9]+\\.[0-9]+)|([0-9]+\\.?)|(\\.?[0-9]+))([+\\-/*](([0-9]+\\.[0-9]+)|([0-9]+\\.?)|(\\.?[0-9]+)))*");
    static Pattern bracePattern = Pattern.compile("\\([^()]+\\)");

    public static boolean matchesForMath(String txt) {

        if (txt == null || txt.isEmpty()) return false;
        txt = txt.replaceAll("\\s+", "");
        if (!txt.contains("(") && !txt.contains(")")) return numberPattern.matcher(txt).matches();
        if (txt.contains("(") ^ txt.contains(")")) return false;
        if (txt.contains("()")) return false;

        Queue toBeRematch = new ArrayDeque<>();
        toBeRematch.add(txt);
        while (toBeRematch.size() > 0) {
            String line = toBeRematch.poll();
            Matcher m = bracePattern.matcher(line);
            if (m.find()) {
                String newline = line.substring(0, m.start()) + "1" + line.substring(m.end());
                String withoutBraces = line.substring(m.start() + 1, m.end() - 1);
                toBeRematch.add(newline);
                if (!numberPattern.matcher(withoutBraces).matches()) return false;
            }

        }
        return true;
    }