(1)1880×201.1-187.9×2011,
=188×2011-187.9×2011,
=(188-187.9)×2011,
=0.1×2011,
=201.1;
(2)
×5÷2 5
×5,2 5
=
÷2 5
×5×5,2 5
=1×5×5,
=25;
(3)
×[8 9
?(3 4
?25%)],7 16
=
×[8 9
-(3 4
?7 16
)],1 4
=
×[8 9
?3 4
],3 16
=
×8 9
,9 16
=
;1 2
(4)7.2×61
+73.8×23 10
,4 5
=7.2×61.3+73.8×2.8,
=441.36+206.64,
=648.