小数混合计算500道(含简算)答案版.docx

小数混合运算+简算

计算题（共19小题）

1.用简便方法计算. 3.7X4.5 - 4.4X3.7

0.25X0.25X4

3.84 - 1.9+0.16 - 1.1

9 - 7F2.5X0.4

5.5X [0.672^ (2+2.2)]

•计算下而各题，怎么简便怎么算. 4.6X5.9+5.9X5.4

24.4X2.5^24.4X0.5

3. 用递等式进行计算， 能简便的要简便简便计算. 7.29X4.6+46X1.271

(28.7 - 18.6^3.1) X0.8

235 - 0.8X31.8

16 - 532 - 4.68

934-3-1^0.3

5. 计算题 12.5X88

50X9.9

3.68 X 68+5.32X68+68

7.15X24.7+7.15X75.3 2005X1.9+200.5X81.

6. 计算（能简算要简算） 2.+8.67+7.36+11.33

2.74 X 9.5+0.5 X 2.7

(2400 - 480X2.5) 一 1.6

7. 脱式计算，能简算的要简算. 42X10.1

(20+8.5) *15

&计算下面各题，能简算的要简算.

90X4.5+45

3.8X1.96 - 3.8X0.46 - 3.8X0.5

(0.125+1.25+12.5+125) X8

9.脱式计算，能简算的要简算. 4.8 —2.04 一 2.4

1.14- (224-5)

25 一 40X0.4

72+0.9 — 0.125

17.37十0.45 ・ 3.8-0.1 9.07 - 22.784-3.4+3.7.

10・计算下列各题 (能用简便算法的要用简便算法).

11.用递等式计算，能简算的要简算. 10.01X101 - 10.01

0.11X1.8+8.2X0.11

26X20.2 - 8.4 - 1.8 12.054-1.254-0.8・

12・怎样简便就怎样计算 3.26X53+0.74X5.3

护 2.7+6\"5+寺

1

+

厲哙）

X】。

1.25X2.8臂.

13・用自己喜欢的方法计算.

720 - 800 — 16 [12 - (34 - 35 ) ]H-710 8.5一[ (1+0.5) X5]

14•下面各题，怎样算简便就怎样算. 2.45 - (1.45+0.)

1.25 X 1.7 X 0.8

5.3X0.82 - 0.82X0.3 3.6一 [12X (0.53 - 0.45)]・

15.下面各题, 0.75X0.5X0.8

怎样简便就怎样计算.

5.6X15.7+9.3X5.6

50.4X1.9 - 1.&

16 •脱式计算, 能简算的要简算

12.8+2.04X9.5 0.15X1999+0.15 0.76X6.5 - 0.76X5.5

78*0.25宁0.4.

17・下而各题怎样算简便就怎样算.

5.4 X 23+5.4 X 7.7

0.25 X32X 12.5

75 子 1.25 一

6.8 X 0.46+0.54 &

18.脱式计算，能简算的要简算. 0.34X101

8.8X1.25

21.9 - 9.28 ・ 10.72

2.94X6.3+3.7X2.94 2.7+C11.2 - 2.7)X0.4 1.5X [0.024-(2.1 - 2.09)].

19・递等式计算，能简便计算的要简便计算. 4.6X25

3.754-12.54-0.8

2.5+7.54-4

(3.2 - 1.4) 4-0.18 - 1.8

7.9X7.1+2.9X7.9

(30.2 ・4.6X5) 4-0.12.

20. 脱式计算（能简算的要简算）. 0.69X4.2+0.69X5.8

6.15X9.4 - 4.2

62.8+2.02X9.5 21. 怎样算简便就怎样算•

17.17 - 6.8 - 3.2 - 6.17 5.4X [ (1.3+2.15) 4-0.2]

16.8X10.1 10.9 - 0.9^0.2+1.8 22. 用递等式进行计算, 算.能简便的要简便简便计

8.4^0.6+8.44-0.4

1.25X3.2X0.25.

0.25X3.8X0.4

3.18 - (0.33+1.18) [1 - (0.5 - 0.25) ] X0.6

23・能简算的要简算. 4.05 一 0.81+2.4；

0.3X4X0.25；

4.02X3.02+4.02X6.98；

0.6X [25 - (8.7 - 3.7) ]•

24.计算下面各题，能用简便算法的用简便算法 (1) 12.25 - 3.1+0.85 - 6.17

(2) (1.9 - 1.9X0.9) 一 (3.8 - 2.8)

(3) 2.65X1.7+1.35X1.7 (4) 0.125X13.8X32X0.25.

25•计算，能简算的要简算. (9.15 - 0.45X3.6) 一0.3

5.639 - 1.732 - 2.268

26.递等式计算.

7.86X1.7 - 0.7X7.86.

小数混合运算+简算

参与试题解析

一.计算题(共19小题)

1.用简便方法计算. 3.7X4.5 - 4.4X3.7 0.25X0.25X4

3.84 一 1.9+0.16 - 1.1 9 - 74-2.5X0.4 5.5X [0.6724- (2+2.2)]

【解答】解：(1) 3.7X4.5 - 4.4X3.7

=3.7X (4.5 -4.4) =3.7X0.1 =0.37；

(2) 0.25X0.25X4 =0.25X (0.25X4) =0.25X1 =0.25；

(3) 3.84 - 1.9+0.16 - 1.1 =(3.84+0.16) - (1.9+1.1) =4・3 =1;

(4) 9 - 7^25X0.4

=9 ・ 1.12

=7.88；

(5) 5.5X [0.672子(2+2.2)] =5.5 X [0.672三4.2] =5.5X0.16

二 0.88.

2•计算下面各题，怎么简便怎么算. 35 - 0.8X31.8 4.6X5.9+5.9X5.4 24.4X2.5H-24.4X0.5

【解答】解:(1) 35 - 0.8X31.8

=35 - 25.44 =9.56

(2) 4.6X5.9+5.9X5.4

=C4.6+5.4) X5.9 =10X5.9 =59

(2) 24.4X2.54-24.4X0.5 =(24.414-24.4) X (2.5 X 0.5) =1X1.25 =1.25

3.用递等式进行计算，能简便的要简便简便计算. 7.29X4.6+46X1.271 (28.7 - 18.-3.1) X0.8 16 - 5.32 - 4.68 3.7X0.125+6.3^8

40.8+14.74- (14.6 - 12.5) 0.72+9.6三3.2

【解答】解：①7.29X4.6+46X1.271

=7.29X4.6+4.6X12.71

二(7.29+12.71) X4.6

=20X4.6 =92；

② (28.7 - 18.-3.1) X0.8

二(28.7 - 6) X0.8

=22.7X0.8 =18.16；

(3) 16 - 5.32 ・ 4.68

=16 - (5.32+4.68) =16 - 10 =6；

④ 3.7X0.125+6.34-8 二 3.7 X 丄+6.3X1

8 8 =(3.7+63) X 丄

8

二 10乂丄

8 虽 4，

⑤40.8+14.74- (14.6 - 12.5)

二 40.8+14.7 —2.1

=40.8+7 =47.8； =3.72.

4. 用递等式计算，能简算的要简算. 28.74-7X4.5 9.6一 (15.4 - 12.2) 4.6X1.2+2.8X4.6 934-3.14-0.3

【解答】解：(1) 28.74-7X4.5 二 4.1X4.5

=18.45

(2) 9.- (15.4 ・ 12.2) =9.-3.2 =3

(3) 4.6X1.2+2.8X4.6 =4.6X (1.2+2.8) =4.6X4 =18.4

(4) 93 — 0.3 =304-0.3 =100

5 •计算题 12.5X88 50X9.9

2005X1.9+200.5X81.

【解答】解：©12.5X88

=12.5 X (80+8)

=12.5X80+12.5X8 =1000+100 =1100

② 50X9.9 =50 X (10 - 0.1) =50X10 - 50X0.1 =500 - 5 =495

③ 3.68X68+5.32X68+68 =(3.68+5.32+1) X68 =10X68 =680

④ 7.15X24.7+7.15X75.3 =7.15 X (24.7+75.3) =7.15X100 =715

⑤ 2005X1.9+200.5X81 =2005X1.9+2005X8.1 =2005 X (1.9+8.1) =2005X10 =20050

6•计算(能简算要简算) 2.+8.67+7.36+11.33 2.74X9.5+0.5X2.7

(2400 - 480X2.5) F1.6 16.8X10.1 1.25X88

6.87X [40一 (3.49 - 3.09)]・

【解答】解：①2.+8.67+7.36+11.33

=(2.+7.36) + (8.67+11.33) =10+20 =30

② 2.74X9.5+0.5X2.7 =26.03+1.35 =27.38

③ (2400 - 480X2.5) 4-1.6 =(2400 - 1200) 4-1.6 =12004-1.6 =750

@16.8X10.1 =16.8 X (10+0.1) =16.8X10+16.8X0.1 =168+1.68 =169.68

=1.25X80+1.25X8 =100+10 =110

⑥ 6.87X[40一 (3.49 ・ 3.09)]

=6.87X [404-0.4] =6.87X100 =687

7.脱式计算，能简算的要简算. 42X10.1 (20+8.5) 4-15

15.4X1.7+9.3X15.4 - 15.4.

【解答】解：@42X10.1

=42 X (10+0.1) =42X10+42X0.1 =420+4.2 =424.2

② (20+8.5)4-15

二 28.5 一 15

=1.9

③ 15.4X1.7+9.3X15.4 - 15.4 =15.4 X 1.7+9.3 X 15.4 - 15.4 X 1 =15.4X (1.7+9.3 - 1) =15.4X10 =154

8•计算下面各题，能简算的要简算. 90X4.5+45

3.8X1.96 - 3.8X0.46 - 3.8X0.5 (0.125+1.25+12.5+125) X8.

【解答】解：(1) 90X4.5+45

=9X45+45

二(9+1) X45

=10X45 =450

(2) 3.8X 1.96 - 3.8X0.46 - 3.8X0.5 =3.8X (1.96 - 0.46 - 0.5) =3.8X1 =3.8

(3) (0.125+1.25+12.5+125)X8 =0.125 X 8+1.25 X 8+12.5 X 8+125 X 8 =1+10+100+1000 =1111

9.脱式计算，能简算的要简算. 4.8^2.044-2.4 1.1^ (224-5) 25 40X0.4 72+0.94-0.125 17.374-0.45 - 3.8-0.1 9.07 - 22.78^3.4+3.7.

【解答】解:(1) 4.84-2.04H-2.4

=24-2.04

=io

51

(2) 1.1^ (22H-5) =1.1^22X5

=0.05X5 =0.25

(3) 25一40X0.4 =25X0.44-40 =104-40 =0.25

(4) 72+0.9 — 0.125 =72+7.2 =79.2

(5) 17.374-0.45 - 3.86-F0.1 =38.6 - 3&6 =0

(6) 9.07 - 22.784-3.4+3.7 =9.07 - 6.7+3.7 =2.37+3.7 =6.07

10・计算下列各题(能用简便算法的要用简便算法). (4.15+0.65) X0.9 (2.3+1.054-2.1) X2.5 9.184-[ (5.9 - 2.3) X0.25].

【解答】解:(1) (4.15+0.65) X0.9

=4.8 X 0.9 =4.32；

(2) 9.06X14.7+5.3X9.06 =9.06 X (14.7+5.3) =9.06X20 =181.2；

(3) (2.3+1.054-2.1) X2.5 =(2.3+0.5) X2.5

二 2.8X2.5

=7；

(4) 9.184-[ (5.9 - 2.3) X0.25] =9.184-[3.6X0.25] =9.184-0.9 =10.2.

11.用递等式计算，能简算的要简算. 10.01X101 - 10.01 0.11X1.8+8.2X0.11 26X20.2 - 8.4 - 1.8 12.05 4-1.25-F0.8.

【解答】解：(1)10.01X101 - 10.01

=10.01 X (101 - 1)

(2) 0.11X1.8+8.2X0.11 =0.11X (1.8+8.2) =0.11X10 =1.1

(3) 26X20.2 - 8.4 - 1.8 =525.2 - (8.4+1.8) =525.2 - 10.2 =515

(4) 12.054-1.254-0.8 =12.054- (1.25X0.8) =12.054-1 =12.05

12.怎样简便就怎样计算 3.26X5.3+0.74X5.3

丄 X2.7+6.3 三 5+丄 5 5 丄 + (1.6+A) X10 3 5

1.25X2.8X-li.

14

【解答】解：(1) 3.26X5.3+0.74X5.3

=(3.26+0.74) X5.3 =4X5.3 =21.2；

(2) 丄X2.7+6.3三5+丄

5 5 =1X2.7+63X1+1X1 5 5 5

=(2.7+6.3+1) X丄

5

二 10><丄

5

=2；

(3) 丄+ (1.6+A) X10

3 5

二丄 + (1.6X10+AX10) 3 5

=1+24 3

二 24 丄；

3

(4) 1.25X2.8X11 =1.25X4X0.7X11

14

14

14

=(1.25X4) X (0.7X11)

二 5X11

20

19 4

13・用自己喜欢的方法计算. 5.6 X 0.7+0.2 X 5.6+0.56 0.9+99 X 0.9 720 - 800*16

X [34 - (716 - 14 )]

[12 - (34 - 35 ) ] 4-710 8.54-[ (1+0.5) X5]

【解答】解:(1)5.6X0.7+0.2X5.6+0.56

=0.56 X 7+2 X 0.56+0.56 X1 =0.56 X (7+2+1) =0.56X10 =5.6；

=0.9X (99+1)

=0.9X100

二 90；

(3) X [34 - (716 ・ 14 )] = X [34 - 702] = X ( - 668) =-59452；

(4) 720 - 8004-16 =720 - 50 =670；

(5) [12 - (34 - 35 ) ] 4-710 = [12 - 34+35] 4-710

= [12+35 - 34] 4-710 =134-710 -13 . 710' (6) 8.54-[ (1+0.5) X5] =8.54-[1.5X5] =8.54-7.5

=27

15* 14.下面各题，怎样算简便就怎样算.

2.45 - (1.45+0.) 1.25X1.7X0.8 5.3X0.82 - 0.82X0.3 3.- [12X (0.53 - 0.45) ]•

【解答】解：(£)2.45 - (1.45+0.)

=2.45 - 1.45 - 0. =1 - 0. =0.11

@1.25X1.7X0.8 =1.25X0.8X1.7 =1X1.7 =1.7

③ 5.3X0.82 - 0.82X0.3 =0.82X (5.3 ・0.3) =0.82X5 =4.1

④ 3.6一 [12X (0.53 - 0.45)] 3.6 —12一 (0.53 ・0.45) =0.3^0.08 =3.75

15・下面各题，怎样简便就怎样计算. 0.75X0.5X0.8 5.6X15.7+9.3X5.6 50.4X1.9 - 1.8.

【解答】解：(1) 0.75X0.5X0.8

=0.75X (0.5X0.8) =0.75X0.4 =0.3；

=5.6X (15.7+9.3) =5.6X25 =14X0.4X25 =14X (0.4X25) =14X10 =140；

(3) 50.4X1.9 - 1.8 =95.76 - 1.8 =93.96.

16•脱式计算，能简算的要简算 12.8+2.04X9.5 0.15X1999+0.15 0.76X6.5 - 0.76X5.5 784-0.254-0.4.

【解答】解：(1)12.8+2.04X9.5

=12.8+19.38 =32.18；

(2) 0.15X1999+0.15 =0.15 X (1999+1) =0.15X2000 =300；

(3) 0.76X6.5 - 0.76X5.5

=0.76X1

=0.76；

(4) 78一0.25子0.4 =784- (0.25X0.4) =784-0.1 =780.

17・下面各题怎样算简便就怎样算. 6.8X0.46+0.54 5.4X2.3+5.4X7.7 0.25X32X12.5 754-1.254-8 ・

【解答】解：(1) 6.8X0.46+0.54

=3.128+0.54 =3.668；

(2) 5.4X2.3+5.4X7.7 =5.4X (23+7.7) =5.4X10 =54；

(3) 0.25X32X12.5 =0.25X (4X8) X12.5 =(0.25X4) X (8X12.5) =1X100 =100；

(4) 75H-1.254-8

=75 \"0 =7.5.

18. 脱式计算，能简算的要简算. 0.34X101 8.8X1.25 2.94X6.3+3.7X2.94 21.9 - 9.28 - 10.72 2.7+ (11.2 - 2.7) X0.4 1.5X [0.02一 (2.1 - 2.09) ]•

【解答】解：(1) 0.34X101

=0.34 X (100+1) =0.34X100+0.34X1 =34+0.34 =34.34；

(2) 8.8X1.25 =(1.1X8) X1.25 =1.1X (8X1.25) =1.1X10 =11;

(3) 2.94X6.3+3.7X2.94 =2.94X (63+3.7) =2.94X10 =29.4；

(4) 21.9 - 9.28 - 10.72

=21.9 - 20 =1.9；

(5) 2.7+ (11.2 - 2.7) X0.4 =2.7+8.5X0.4 =2.7+3.4 =6.1；

(6) 1.5X [0.024- (2.1 - 2.09)] =1.5X [0.024-0.01] =1.5X2 =3.

19. 递等式计算，能简便计算的要简便计算. 4.6X25

3.75 — 12.5 — 0.8 2・5+7.5 宁 4 (3.2 - 1.4) 4-0.18 - 1.8 7.9X7.1+2.9X7.9 (30.2 - 4.6X5) 4-0.12.

【解答】解：(1)4.6X25

=(4+0.6) X25 =4X25+0.6X25 =100+15 =115；

(2) 3.754-12.54-0.8

=0.375；

(3) 2.5+7.54-4 =2.5+1.875 =4.375；

(4) (3.2 - 1.4) 4-0.18 - 1.8 =1.84-0.18 - 1.8 =10 - 1.8 =8.2；

(5) 7.9X7.1+2.9X7.9 =7.9X (7.1+2.9) =7.9X10 =79；

(6) (30.2 - 4.6X5) 4-0.12 =(30.2 - 23) 4-0.12

二 7.2 = 0.12

=60.

二.解答题(共7小题)

20. 脱式计算(能简算的要简算).

0.69X4.2+0.69X5.8 (8+0.8) X1.25 4.95+12.08 - 5.37 6.15X9.4 - 4.2

62.8+2.02X9.5 0.25X3.8X0.4

【強军答】ft?： (1) 0.69X4.2+0.69X5.8

=0.69X C4.2+5.8)

=6.9

(2) (8+0.8) X1.25 =8X1.25+0.8X1.25 =10+1 =11

(3) 4.95+12.08 - 5.37 =17.03 - 5.37 =11.66

(4) 6.15X9.4 - 4.2 =57.81 - 4.2 =53.61

(5) 62.8+2.02X9.5 =62.8+19.19 =81.99

(6) 0.25X3.8X0.4 =(0.25X0.4) X3.8 =0.1X3.8 =0.38

21.

怎样算简便就怎样算.(12%) 5.4X [ (1.3+2.15)

17.17 - 6.8 - 3.2 ・ 6.17 16.8X10.1

10.9 - 0.94-0.2+1.8

【解答】解：(1) 17.17 - 6.8 - 3.2 - 6.17

一0.2] 8.44-0.6+8.4^0.4

1.25X3.2X0.25.

=11 - 10, =1;

(2) 5.4X [ (1.3+2.15) 4-0.2] =5.4X [3.454-0.2], =5.4X17.25, =93.15；

(3) 8.44-0.6+8.4^0.4 =14+21 =35；

(4) 16.8X10.1 =16.8X10+16.8X0.1, =168+1.68, =169.68；

(5) 10.9 - 0.94-0.2+1.8 =10.9 - 4.5+1.8, =8.2；

(6) 1.25X3.2X0.25 =(1.25X0.8) X (4X0.25), =1X1,

二1・

22.用递等式进行计算，能简便的要简便简便计算. 0.25 X (0.4+40)

0.67+1.28+9.33+0.72

3.18 - (0.33+1.18) [1 - (0.5 - 0.25) ] X0.6

【解答】解:(1) 0.25X (0.4+40),

=0.25X0.4+0.25X40, =0.1+10,

(2) 0.67+1.28+9.33+0.72,

二(0.67+9.33) + (1.28+0.72),

=10+2, =12；

(3) 3.18 ・(0.33+1.18), =3.18 - 0.33 - 1.18, =(3.18 - 1.18) - 0.33, =2 - 0.33, =1.67；

(4) [1 - (0.5 - 0.25) ] X0.6, =[1 - 0.25] X0.6, =0.75X0.6,

二 0.45・

23.

能简算的要简算.

4.05^0.81+2.4；

0.3X4X0.25；

4.02X3.02+4.02X6.98； 0.6X [25 - (8.7 - 3.7)].

【解答】解：(1) 4.054-0.81+2.4

=5+2.4 =7.4；

(2) 0.3X4X0.25 =0.3X (4X0.25) =0.3X1 =0.3；

(3) 4.02X3.02+4.02X6.98 =4.02 X (3.02+6.98) =4.02X10 =40.2；

(4) 0.6X [25 ・(8.7 - 3.7)] =0.6X [25 - 5] =0.6X20 =12.

24.

计算下面各题，能用简便算法的用简便算(2) (1.9 - 1.9X0.9) 一 (3.8-2.8) 法

(1) 12.25 - 3.1+0.85 - 6.17 (3) 2.65X1.7+1.35X1.7

(4) 0.125X13.8X32X0.25.

【解答】解:(1) 12.25 - 3.1+0.85 - 6.17

=12.25+0.85 - 3.1 - 6.17 =13.1 - 3.1 - 6.17 =10 - 6.17 =3.83；

(2) (1.9 - 1.9X0.9) 4- (3.8 - 2.8) =(1.9 - 1.71) 一 (3.8 - 2.8) =0.194-1 =0.19；

(3) 2.65X1.7+1.35X1.7

=(2.65+1.35) X1.7

二 6.8；

(4) 0.125X13.8X32X0.25 =0.125X8X (4X0.25) X13.8 =1X1X13.8 =13.8.

25.

计算，能简算的要简算.17.6-0.5X0.5-0.75

(9.15 - 0.45X3.6) 4-0.3 5.639 - 1.732 - 2.268

7.86X1.7 - 0.7X7.86.

【解答】解：①(9.15 - 0.45X3.6) 4-0.3

=(9.15 - 1.62) 4-0.3 =7.53^0.3 =25.1

(2)17.6 - 0.5 X 0.5 - 0.75 =17.6 - 0.25 - 0.75 =17.6 - (0.25+0.75) =17.6 - 1 =16.6

③5.639 - 1.732 - 2.268 =5.639 - (1.732+2.268) =5.639 - 4 =1.639

@7.86X1.7 - 0.7X7.86 =7.86X (1.7 - 0.7)

=7.86X1 =7.86

26.递等式计算. 0.11X1.8+8.2X0.11, 0.8X (3.2 ・ 2.99一2.3) 5.4一 (3.94+0.86) X0.8・

【解答】解：(1) 0.11X1.8+8.2X0.11

=0.11 X (1.8+8.2) =0.11X10 =1.1

(2) 0.8X (3.2 - 2.994-2.3) =0.8X (3.2 - 1.3) =0.8 X 1.9 =1.52

(3) 5.4一 (3.94+0.86) X0.8

二 5.4 — 4.8X0.8

=1.125X0.8 =0. 9