private function parseAddition (){

		$return = $m = $this->parseMultiplication();
		if( $return ){
			while( true ){

				$isSpaced = $this->isWhitespace( -1 );

				$op = $this->MatchReg('/\\G[-+]\s+/');
				if( $op ){
					$op = $op[0];
				}else{
					if( !$isSpaced ){
						$op = $this->match(array('#+','#-'));
					}
					if( !$op ){
						break;
					}
				}

				$a = $this->parseMultiplication();
				if( !$a ){
					break;
				}

				$m->parensInOp = true;
				$a->parensInOp = true;
				$return = $this->NewObj3('Less_Tree_Operation',array($op, array($return, $a), $isSpaced));
			}
		}

		return $return;
	}