(1)
(-81)÷(+3又1/4)×(-4/9)÷(-1又1/13)
=(-81)÷(13/4)×(-4/9)÷(-14/13)
=(-81)×(4/13)×(-4/9)×(-13/14)
=-72/7
(2)
(-3)的三次方÷2又1/4×(-2/3)的二次方+4-2×(-1/3)
=(-27)×(4/9)×(4/9)+4+2/3
=-16/3+4+2/3
=-2/3
(3)
-1的四次方-(1-0.5)×1/3×【2-(-3)的二次方】
=-1-0.5×(1/3)×(-7)
=-1+7/6
=1/6
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