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338×9−3−0.375999×222+333×3341214-(1214-(325+2.25-3.6)63:6=x−15x-49-59x=23已知a=8.8+8.98+8.998+8.9998+8.99998,求a的整数部分.

题目详情
3
3
8
×9−3−0.375          
999×222+333×334              
12
1
4
-(12
1
4
-(3
2
5
+2.25-3.6)
 
6
3
:6=
x−1
5
                                    
x-
4
9
-
5
9
x=
2
3

已知a=8.8+8.98+8.998+8.9998+8.99998,求a的整数部分.
▼优质解答
答案和解析
(1)3
3
8
×9-3-0.375,
=(3+0.375)×9-3-0.375,
=3×9+0.375×9-3-0.375,
=27-3+(9-1)×0.375,
=24+8×
3
8

=24+3,
=27;

(2)999×222+333×334,
=333×3×222+333×334,
=333×(666+334),
=333×1000,
=333000;

(3)12
1
4
-[12
1
4
-(3
2
5
+2.25-3.6)],
=12
1
4
-12
1
4
+(3
2
5
+2.25-3.6),
=3.4+2.25-3.6,
=2.05;

(4)
6
3
:6=
x−1
5

      1:3=(x-1):5,
3×(x-1)=5,
      3x-3=5,
    3x-3+3=5+3,
        3x=8,
     3x÷3=8÷3,
         x=
8
3


(5)x-
4
9
-
5
9
x=
2
3

   x(1-
5
9
)-
4
9
=
2
3

x(1-
5
9
)-
4
9
+
4
9
=
2
3
+
4
9

           
4
9
x=
10
9

       
4
9
9
4
=
10
9
×
9
4

              x=
5
2


(6)a=8.8+8.98+8.998+8.9998+8.99998,
=(9-0.2)+(9-0.02)+(9-0.002)+(9-0.0002)+(9-0.00002),
=9×5-0.22222,
=45-0.22222,
=44.77778,
所以a的整数部分是44.