1, 2.5+0.9 = 3.6+4.9 = 5.6 4.8 = 31.6 = 3.06+4.4 = 8.8+4.5 = 5.2+4.8 = 32.9 = 2, Calculate the following problems and check 3.64+1 .48 22.32+12.59 7.85+1Calculate the following problems with decimals: 5 yuan 60.3+3.09+ 1 ton 30 kg +980 kg 4 m 35 cm +5 m 70 cm. 0 kg +4 kg 800 g 4 km 800 m -3 km 50 m 6 km -4 km 860 m (Editor: Wind) 1, 2.1.2 = 0.3+0.7 = 3.6+1.6 = 0.6 (1). 5.85-1.75-0.25 (4) 768-274-126 (5) 5.85+1.89+2.15 (6) 24 Distinguish right from wrong. (1) integer additive commutative law and associative law are also applicable to decimal-() (2) 4.72+0.1-4.72+0.1= 0-. If the decimal part of the number has 0, it should be removed from 0-()(4) The mixed operation of decimal addition and subtraction must be calculated first-() Fifth, solve the problem. 1. One morning, the temperature was 6.5℃, which was 3. 1℃ higher at noon and 4.5℃ lower at night than at noon. What is the temperature tonight? 2. Mom spent 5.8 yuan on fruits, 2.6 yuan on vegetables and 5.2 yuan on fish, more than the sum of fruits and vegetables. How much did she spend on fish? 3. Students in Qian Lou Central Primary School collect tree species on Sundays. In the first week, they collected 2.8 kilograms, and in the second week, they collected 0. 13 kilograms less than in the first week. How many kilograms were collected in two weeks? Xiao Ming's father bought a bottle of salad oil, 3.4 kilograms. Half of the oil is used, and the bottle weighs 1.9 kg. Do you know how many kilograms this bottle of oil used to have? How much does this bottle weigh? 5. Xiao Fang went to the bookstore to buy books, paid 30 yuan and got back 26.4 yuan. Xiao Fang found that the salesgirl gave her 2 1.8 yuan and asked the salesgirl how much she should actually give Xiao Fang. What's the price of this book? 6. The average height of the fourth grade boys in Qian Lou Central Primary School is 122.8cm, and the third grade boys are shorter than the fourth grade boys14.2cm.. Wu Haoran is a boy in Class Two, Grade Three, and his height is1.25m. How much taller is Wu Haoran than the boy in Grade Three? The report supplemented the respondents 2010-08-0616: 205+1= 5+7 = 5+9 = 9+8 = 4+6 =

3+ 1= 3+7= 7+4= 1+8= 3+5=

3+6= 6+7= 6+3= 6+5= 5+9=

6+3= 8+2= 5+4= 9+5= 2+6=

5+2= 3+9= 5+5= 8+2= 5+9=

4+8= 6+ 1= 9+3= 9+8= 8+3=

7+2= 1+9= 8+4= 2+4= 4+5=

3+4= 9+9= 4+8= 9+3= 9+9=

8+9= 5+2= 5+5= 2+8= 8+4=

9+2= 7+ 1= 2+6= 6+9= 1+8=

2+5= 5+5= 7+8= 6+5= 3+5=

2+8= 4+5= 1+4= 9+8= 1+2=

1+3= 7+8= 7+5= 1+2= 6+4=

3+5= 9+2= 4+ 1= 3+7= 1+9=

2+9= 9+5= 5+9= 5+7= 3+ 1=

2+6= 4+9= 2+ 1= 2+3= 7+7=

1+3= 8+9= 2+8= 3+2= 2+4=

7+9= 6+4= 8+9= 7+6= 9+5=

4+3= 6+2= 3+6= 8+6= 4+3=

3+9= 7+4= 4+4= 7+ 1= 7+ 1=

8+5= 5+9= 6+9= 5+5= 4+7=

8+8= 2+9= 7+ 1= 2+7= 8+5=

The report supplemented the respondents 2010-08-0616: 215+1= 4+2 = 8+3 = 4+2 = 6+7 =

4+4= 3+8= 4+4= 8+5= 4+9=

4+ 1= 2+2= 7+2= 4+5= 8+4=

4+6= 9+7= 1+9= 5+3= 2+9=

5+2= 3+4= 5+5= 1+7= 6+ 1=

6+6= 9+8= 2+3= 7+8= 5+8=

9+3= 3+ 1= 6+3= 9+9= 1+2=

3+2= 9+3= 3+ 1= 7+5= 8+4=

3+2= 6+9= 8+7= 7+8= 8+3=

8+7= 8+3= 2+4= 7+5= 9+4=

The report supplemented the respondents 2010-08-0616: 23 280+650 ÷1000-(280+650 ÷13).

707 - 35 × 20 ( 120 - 103)× 50

760 ÷ 10 ÷ 38 (95 - 19 × 5 )÷74

45 × 20 × 3 (270 + 180)÷(30 - 15)

3 1.50+ 160÷40 (58+370)÷(64-45)

32. 120- 144÷ 18+35

33.347+45×2-4 160÷52

34 (58+37)÷(64-9×5)

35 .95÷(64-45)

36. 178- 145÷5×6+42 420+580-64×2 1÷28

37.8 12-700÷(9+3 1× 1 1) ( 136+64)×(65-345÷23)

38.85+ 14×( 14+208÷26)

39.(284+ 16)×(5 12-8208÷ 18)

40 . 120-36×4÷ 18+35

4 1.(58+37)÷(64-9×5)

42 .(6.8-6.8×0.55)÷8.5

43.0. 12× 4.8÷0. 12×4.8

44. (3.2×1.5+2.5) ÷1.63.2× (1.5+2.5) ÷1.6 Supplementary applicant 201.

49.5.8×(3.87-0. 13)+4.2×3.74

50.32.52-(6+9.728÷3.2)×2.5

2356-( 1356-72 1) 1235-( 1780- 1665) 75×27+ 19×2 5

3 1.50+ 160÷40 (58+370)÷(64-45)

32. 120- 144÷ 18+35

33.347+45×2-4 160÷52

34(58+37)÷(64-9×5)

35.95÷(64-45)

36. 178- 145÷5×6+42 420+580-64×2 1÷28

37.8 12-700÷(9+3 1× 1 1) ( 136+64)×(65-345÷23)

38.85+ 14×( 14+208÷26)

39.(284+ 16)×(5 12-8208÷ 18)

40. 120-36×4÷ 18+35

4 1.(58+37)÷(64-9×5) Report Respondents Supplemented 20 10-08-06 16:26 III. Comparative calculation:

49 + 17 - 25 240 ÷ 40 × 5 300 - 50 × 2

49 - ( 17 + 25) 240 + 40 × 5 300 - 50 × 20 × 0

Four, off-type calculation:

12 1 - 1 1 1 ÷ 37 ( 12 1 - 1 1 1 ÷ 37)× 5

640÷80=

15×5=

23×3=

12×2×5=

480÷80=

16×5=

27×3=

90÷ 15=

48÷4=

640÷ 16=

39÷3=

24×20=

32×3=

48÷ 16=

12×8=

27×3=

56÷ 14= informant supplement 2010-08-0616: 27 24÷ 8 =

14×2=

83-45=

560÷80=

96÷24=

40÷20=

40×30=

37+26=

76-39=

605+59=

30×23=

12×8=

27+32=

48+27=

4500×20=

73+ 15 =

120×600 =

200×360=

6800×400=

280+270=

4×2500=

6000÷40=

5× 1280=

4.3+2.7=

0.75+0.25=

4-0.26=

0.35+2.7=

4.6- 1.9=

0.83-0.3=

3+0.05=

7.2-3.8=

0.07+0.6=

26- 12+24=

22+35+29=

57-38+ 15=

80- 12- 14=

32-27+86=

36+27-48= Supplement to the report respondents 2010-08-0616: 29 65+35-34 =

72-35+26=

86-37+20=

54- 13+37=

39-20+77=

10+56-30=

12+6+50=

66- 10=

13+5 1=

82+5=

75-22=

79+ 14=

80-4=

69- 18=

84-20=

9 1-7 1=

89+0=

1 1+7 1=

10+75=

36+62=

73-45=

64-46=

90-60=

73-20=

93-8 1=

19+44=

55-48=

72+2 1=

50+24=

86-76=

65+35=

76+ 15=

13+ 18=

26+2 1=

100-87=

84-82=

27+ 18= informant's supplement 2010-08-0616: 30 61+34 =

47-6=

47+32=

72-35=

88-3 1=

94+0=

24- 12=

52+20=

75-34=

75-57=

42+45=

74- 17=

67+22=

7 1+23=

76-35=

58-50=

49+26=

89-46=

13+64=

48+43=

5 1+36=

59-39=

17+50=

55- 10=

18+82=

1 1+85=

37+97=

75-5 1=

68-47=

9 1-6 1=

74-29=

94-83=

20+59=

60-50=

73+79=

52+54=

87-78=

67+99=

77+67=

14+29=

27+36=

88+ 1 1=

86-84=

28+33=

62+88=

48- 17=

56+ 16=

48+66=

35+ 13= informant's supplement 2010-08-0616: 32 75-36 =

90-32=

95+ 12=

32- 13=

53+48=

78-36=

78-58=

43+80=

75-26=