関連ワード:  do a negative and a negative equal a positive    does a negative and a negative equal a positive    does a negative and a negative equal a positive in addition    does a negative and a negative always equal a positive    do a negative plus a negative equal a positive    do a negative times a negative equal a positive    does a negative minus a negative equal a positive    does a negative over a negative equal a positive    does a negative divided a negative equal a positive    does a negative plus a negative equal a positive number  
結果 : do a negative and a negative equal a positive