protected function askNumeric( $question, $default = null ) {
		$ask = 'Your answer needs to be a numeric value';

		if ( ! is_null( $default ) ) {
			$question .= ' [Default: '. $default .'] ';
			$ask .= ' or blank for default';
		}

		$answer = $this->ask( $question );

		while ( ! is_numeric( $answer ) and ! ( $answer == '' and ! is_null( $default ) ) ) {
			$answer = $this->ask( $ask .'. ');
		}
		if ( $answer == '' ) {
			$answer = $default;
		}
		return $answer;
	}