private String decode999( int num ) {
		String s = "";		
		// work out hundreds : numbers 100-900
		int n = num % 1000;   // extract the first 3 digits from num
		if ( n >=100 ) s += units[ n / 100 ] + " hundred";		
		if ( n>=100 && n % 100 != 0 ) s+= " and ";
		
		// numbers 1-99
		n = num % 100;  // extract the first 2 digits from num
		if ( n < 10 ) s+= units[ n % 10 ];
		// special case numbers 11-19
		if ( n >= 11 && n <=19 ) s+= teens[ n % 10 ];
		// everything else
		if ( n==10 || n>=20 ) {
			s += tens[ (n/10) % 10 ];		
			if ( n % 10 != 0 ) s += " " + units[ n % 10 ];
		}		
		return s;		
	}