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能简算的要简算. 2.87+5.6-0.87+4.4  1118

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能简算的要简算.
2.87+5.6-0.87+4.4  
11
18
能简算的要简算. 2.87+5.6-0.87+4.4  1118
(1)2.87+5.6-0.87+4.4,
=(2.87-0.87)+(5.6+4.4),
=2+10,
=12;
(2)
11
18×9-
11
18×6,
=(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

4
3,
=
9
10-
4
5,
=
1
10;
(5)
1
2x+
3
5x=4.4,
  (
1
2+
3
5)x=4.4,
      
11
10x=4.4,
 
11
10x÷
11
10=4.4÷
11
10,
          x=4.4×
10
11,
          x=4.