(1)1.25×32×0.25
=1.25×8×4×0.25
=(1.25×8)×(4×0.25)
=10×1
=10
(2)1.8×
+2.2×25% 1 4
=1.8×
+2.2×1 4
1 4
=(1.8+2.2)×
1 4
=4×
1 4
=1
(3)[1-(
-1 2
)]×1 4
2 3
=[1-
]×1 4
2 3
=
×3 4
2 3
=
1 2
(4)12×[(
-11 6
)×3]2 3
=12×[
×3]7 6
=12×
7 2
=42