String percent() {
	    cleanX = true;
	    cleanY = true;
	    endZero = "";
	    if (enterX) {
	        x = 0.01 * result;
	        return format(x);
	    } else if (! canCalculate) {
	        if (equalCalled) {
	            x = 0.01 * result;
	            y = 0;
	            return format(x);
	        }
	        else {
	            y = 0.01 * x * y;
	            return format(y);
	        }
	    } else {
	        y = 0.01 * x * y;
	        return format(y);
	    }
	}