脱式计算,能简算的就简算.
38
125×83-25×15. |
(1)
÷[7 12
-(3 4
-11 20
)],1 2
=
÷[7 12
-3 4
],1 20
=
÷7 12
,7 10
=
;5 6
(2)38
-15.38+61.25-4.62,3 4
=(38
+61.25)-(15.38+4.62),3 4
=100-20,
=80;
(3)
×5.65+3.35×1 8
+1 8
,1 8
=
×(5.65+3.35+1),1 8
=
×10,1 8
=
;5 4
(4)125×83-25×15,
=(25×5)×83-25×15,
=25×415-25×15,
=25×(415-15),
=25×400,
=10000.