(-24) [0.125-(-2又1/3)+5/6+(-3/8)]
=(-24) [1/8-(-7/3)+5/6-3/8]
=(-24) ( 1/8+7/3+5/6-3/8 )
=-24×1/8-24×7/3-24×5/6+24×3/8
=-3-56-20+9
=9-(3+56+20)
=9-79
=-70
已知|a-b|=a-b,且|a|=2,|b|=5
则 a=±2,b=±5 且 a-b﹥0
所以 a=±2,b=-5
当a=2,b=-5时：
a-b=2-(-5)
=2+5
=7
当a=-2,b=-5时：
a-b=-2-(-5)
=-2+5
=3
所以,a-b的值为7或3