神机妙算:0.8×6.5-45×3.5(115+79)×451-815÷45+2325×1.25×3299×910+9101914-78-18.-数学
题文
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答案
(1)0.8×6.5-
=0.8×6.5-0.8×3.5, =(6.5-3.5)×0.8, =3×0.8, =2.4; (2)(
=
=3+35, =38; (3)1-
=1-
=1-
=1; (4)25×1.25×32, =25×1.25×8×4, =25×4×(1.25×8), =100×10, =1000; (5)99×
=(99+1)×
=100× |