能简算的要简算. 2.87+5.6-0.87+4.4 11/18×9-11/18×6 420÷7÷6 9/10-( 1/4+7/20)÷3/4 1/2x+3/5x=4.4(解方程)
问题描述:
能简算的要简算.
2.87+5.6-0.87+4.4 |
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420÷7÷6 | |||||||||||
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答
(1)2.87+5.6-0.87+4.4,
=(2.87-0.87)+(5.6+4.4),
=2+10,
=12;
(2)
×9-11 18
×6,11 18
=(9-6)×
,11 18
=3×
,11 18
=
;11 6
(3)420÷7÷6,
=420÷(6×7),
=420÷42,
=10;
(4)
-(9 10
+1 4
)÷7 20
,3 4
=
-9 10
×3 5
,4 3
=
-9 10
,4 5
=
;1 10
(5)
x+1 2
x=4.4,3 5
(
+1 2
)x=4.4,3 5
x=4.4,11 10
x÷11 10
=4.4÷11 10
,11 10
x=4.4×
,10 11
x=4.