七年级数学有理数的乘法简便计算(-6)×(-3 1/2)-(-7)×3 1/7+13×(-3 4/13)

问题描述:

七年级数学有理数的乘法简便计算
(-6)×(-3 1/2)-(-7)×3 1/7+13×(-3 4/13)

=-6×(-2/3)+7×3/7+13×(-12/13)
=21 + 22 - 43
=0

(-6)×(-3 1/2)-(-7)×3 1/7+13×(-3 4/13)
=6×7/2 + 7×22/7 - 13×43/13
=21 + 22 - 43
=0

=-6×(-2/3)+7×3/7+13×(-12/13)
=9+3-12=0