若干個有理數(shù)相乘,其積是負數(shù),則負因數(shù)的個數(shù)是________.
奇數(shù)
分析:根據(jù)有理數(shù)的乘法的符號法則進行判斷.
解答:由幾個不為零的有理數(shù)相乘的法則可知,當(dāng)負因數(shù)有奇數(shù)個時,積為負.
例如:(-1)×(-2)×(-3)×4=-24,有3個負因數(shù),其積為負數(shù).
點評:本題考查了有理數(shù)的乘法法則:幾個不等于0的數(shù)相乘,積的符號由負因數(shù)的個數(shù)決定.當(dāng)負因數(shù)有奇數(shù)個時,積為負;當(dāng)負因數(shù)有偶數(shù)個時,積為正.