999又25分之24乘以负5
=999又24/25×(-5)
=(999+24/25)×(-5)
=999×(-5)+24/25×(-5)
=(1000-1)×(-5)-24/5
=1000×(-5)-1×(-5)-24/5
= -5000+5-4又4/5
= -4999又4/5
负5乘以7又3分之1加7乘以负7又3分之1减12乘以7又3分之1
=(-5)×7又1/3+7×(-7又1/3)-12×7又1/3
=(-5)×7又1/3-7×7又1/3-12×7又1/3
=(-5-7-12)×7又1/3
= -24×22/3
= -176