1. Cuboid and cube?
Click the classroom?
Page 1 25 cm?
Page iii, 1. A 2。 C 3,1.1.350 cm2. 3.9 square centimeters 3. 160 cm2.
4.12m2 5. 302.5 square decimeter?
Page 5 III. 1. 180㎡ 196㎡58.8kg 2.40㎡？
Page 6. 1.40 square decimeter 2. 1.820 square meter 3. 6 square meters 0.5 kg 4. 250 square centimeters five. 2,900 square centimeters. 52 square decimeters?
Page 8 2, 1. 2.╳ ? 3.√? 4.╳ ? 5.╳ ? 6.╳
1 1 Page 5, 1. 2240 cubic centimeters. 2000 cubic meters 3. 2 16 cubic decimeter?
Page 15 III. 1.3 cubic decimeter 2. 126 kg?
Page 16 II. 1.√? 2.╳? 3.√? 4.╳
Page 18 II. 1.√? 2.╳? 3.√? 4.╳? 5.╳
Page 22, two to six copies?
Extend the application?
page 1 50×2+30×2+ 10×4+30 = 230(cm)？
Page 2, page 4, page 3 12?
Page 4 Tin box surface area: 4× 4× 5 = 80 (square centimeter) Square tin area: 4× 3 = 12 (centimeter) 12 = 144 (square centimeter)?
Page 5 (15× 3×11+15× 3× 7+1× 7) × 2 =1774 (square centimeter
Page 7 5× 5× 6+2× 2× 4 = 166 (square centimeter)?
Page 9 1. 7 4 5 3.8?
Page1115×10× 8-15× 4× 2 =1080 (cubic centimeter)?
Page 13 20× 15 = 6000 (cubic centimeter) or 20×15 = 4500 (cubic centimeter)?
Page 14 80 ÷ 4 ÷ 4 = 5 (decimeter) (4+5) × 5 × 5 = 225 (cubic decimeter)?
Page 15 Height: (70-9.8× 2) ÷ 12.6 = 4 (decimeter) Volume: 9.8× 4 = 39.2 (cubic decimeter)?
page 17 18÷3 = 6(a)7÷3≈2(a)6÷3 = 2(a)6×2×2 = 24(a)？
Page 19 (44-2× 2 )× (29-2× 2 )× (32-2) = 30000 (cubic centimeter)?
page 2 1 0. 18×2×60 = 2 1.6(m3)？
Page 22: Three-sided painting: 4 double-sided paintings: 4× 4+5× 4 = 36 (sheets)?
1 top coating: 4× 4+4× 5× 4 = 96 (pieces) 6 sides not coated: 4× 4× 5 = 80 (pieces)?
Unit exercise?
Second, 1. √? 2.╳ ? 3.╳ ? 4.╳ 5.╳? 6.╳ ? 7.√
Third, 1. C 2。 B 3。 B 4。 C 5。 C 6。 C 7。 Answer?
Volume: 48 cubic centimeters Surface area: 88 square centimeters?
Verb (abbreviation of verb)1.70mm21kg 2. 337.5 kg 3。 125cm 4. 2 100 square centimeter 5. 5040 pieces of 6. Four cents and seven meters. 0.5 cm 8. 126 cm2 9. 2.5 cm 6544.
11.217.6 < 220, which is not true?
Second, decimal multiplication?
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Page 27 III. 1.8132.6438+06m2?
Page 28 II. 1.56 2.48 years old 18 years old?
Page 29 II. 1. 15 2.24 trees?
Page 30 III. 1.92 decimeter 2. 35 kilometers, 23 kilometers?
Page 3 1 3. 1.( 1) 16 square decimeter (2) 12 16 cubic decimeter 2. 49 hectares?
Page 32 III. 1.532 m2. 15 people?
Page 33 IV. 1.145ton2. 140?
Page 34 2. 1.A 2。 C 3。 B 4。 Answer?
Page 36 I. 1. √? 2.√ 3.╳? 4.√
Extend the application?
Page 27 59× 18× 59 = 509 (square meters)?
Page 28 1-423× 5 = 323?
Page 29 2200-2200×11= 2000 (yuan)?
Page 301225× 512 = 15 (cubic meters)15 cubic meters = 200 liters?
Page 3145× 35×16 = 225 (m3)?
Page 32 48× 58+48×1724-48 =16 (person)?
Page 33 1.85 1A2 23 47 2. < 1 > 1 = 1?
Page 35 C > B > A > D?
Page 36 A car is nearly 80 kilometers?
Unit exercise?
Second, 1. 2.√ ? 3.√? 4.√? 5.╳
Three. 527 133 29 38?
4. 1.500 2. 154 3.20cm 16cm？
Third, fractional division?
Click the classroom?
Page 39 III. 1. 1 100 m2. 127?
Page 40 III. 1.800 pack of two. Seven days?
Page 4 1 3. 1.( 1)56 hours (2)65 tons 2. 10 pairs?
Page 42 II. 1.30 km2. 2 16 ton 3. 300 tons?
Page 44 III. 1.(1) 80km (2)100km2. 1 19 Page 3. 325kg 532kg？
Page 45 III. 1.25 18 km2. 18 decimeter 3. 72 years old?
Page 46 II. 1.√? 2.√? 3.╳? 4.╳
Page 48 III. 1.24: 22 2.27: 8?
Page 49 II. 1. 16 people, 20 people, 2. 120kg, 280kg, 200kg?
Page 50 II. 1.200m 160m 2. 100 m2 3。 20 degrees
Page 5 1 page II. 1.√? 2.√ ? 3.√ ? 4.╳
Page 53 II. 1.√? 2.╳ ? 3.╳? 4.╳
Page 55 III. 1.B 2。 A 3。 B 4。 B 5。 c？
Extend the application?
Page 39 37 ÷ 6 = 376 (kg)?
Page 401÷19 = 91÷12 =12?
page 4 1 65÷( 13- 1)= 1 10(km)？
Page 42 25 ÷ 34 = 8 15?
Page 44 10 ÷ 57 = 14 (days)?
Page 45 150× 35 ÷ 57 = 126 (Ben)?
Page 46, 8: 7?
Page 47 15: 35?
Page 48 9: 10?
Page 49 480 ÷ 2 ÷ 4 = 60?
Page 52 37× 47 ÷ 2 = 649 (square centimeter)?
Page 54 5 ÷ 17-5 = 30 (kg)?
Page 56 14 ÷ 7× 8 = 16 (person)?
Unit exercise?
Second, 1. B 2。 A 3。 C 4 explosive A 5。 d？
Three. 1.√? 2.√? 3.╳ ? 4.╳
Four. 1.32 15 148 44 58 10 125 32.35 3365 12 3. 10: 2 1:
Verb (abbreviation of verb) on page 1. 252: 2.70 basket: 3. 42 kilograms: 4. 449 square decimeters: 5. 250 books: 6. 4 15 hectare.
7.72 square meters. 324?
Fourth, the strategy to solve the problem?
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Page 6 1 Page 2. 1. Volleyball: 20 yuan Basketball: 40 yuan 2. Flour: 25 kg rice: 50 kg?
3. Ballpoint pen: 4 yuan pen: 16 yuan?
Page 62: 1. Small box: 15 large box: 20 twos. Pear: 1.8 yuan Apple: 2.4 yuan?
3. Back row: 25 yuan Front row: 40 yuan?
Page 63 I. 1.32.32-O2.32A+3?
Extend the application?
Page 6 1 6 ÷ 3× 2 = 4 (box) chocolate: 24 ÷ (4+4) = 3 (yuan) potato chips: 3× 2 ÷ 3 = 2 (yuan)?
Page 62 9 red balloons, 14 blue balloons and 7 yellow balloons?
Page 64 VCD Book: 1000 Yuan Hardcover Book: 500 yuan Paperback Book: 250 yuan?
Unit exercise?
Second, 1.b2.d3.b4.a?
Three. 1.43 76 25 45 15 124 12 547 16 830 2. 123 14 6 3957.
3.x = 200 x = 2 x = 10.62 x = 6. 1？
4. 1. Table tennis racket: 20 yuan basketball: 80 yuan 2. Small box: 16 large box: 2 1?
3. Piglet: 12kg No dog: 8kg 4. 180kg 5。 Skirt: 67.5 Yuan Shirt: 90 yuan?
6.2 1 sheet 7. 8 yuan 8. Apprentice: 15 Master: 25?
5. What is the score of elementary arithmetic?
Click the classroom?
Page 69 II.1.114153515215531581565438.
2.334 1275 85 18 16 3.307 5 49 203?
Page 72 II. Page 1. 16 2. 16km 3.35438+00L？
Page 76 2. 2.240?
Page 77 II. 1.2 16 2.60kg 3。 ( 1) 550m 870m (2) 290m？
Page 78 II. 1. (1)136 (2)1day 4 (3)45 2. 20 minutes. 12 kg?
Page 80 III. 1.32500 unit with 2. 6 1 person?
Extend the application?
Page 7014+72×12 =1+3×13 = 2 (the answer is not unique)?
Page 72 a?
Page 75 215×12-215× 25 = 21.5 (km)?
Page 76100 ÷ 235-100 =1650 (yuan)?
Page 77 120× 58+23- 1 = 35 (name)?
Page 79 80× 34+80 = 140 (pieces)?
Page 80 24× 1-38- 14 = 9 (decimeter)?
Unit exercise?
Second, 1. 2.╳? 3.╳ ? 4.╳ ? 5.√
Third, 1. B 2。 B 3。 C 4 explosive b？
Four. 1. 16 3625 10 35 18 32 498 1 562. 126 139 255 244 3.X = 340x = 9 14。
x=67 x=9？
Verb (abbreviation of verb)1.(1) 70 ÷ 25 (2) 350-350× 37 2.1kg 3. 38 tons. 80 meters, 88 meters and 5 meters. 140 kg?
6.260 sets of 7. Forty people. Chair 105 Yuan Table 175 yuan?
6. percentage?
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Page 85 II. 1.2.╳ ? 3.√ ? 4.√
Page 87 II. 1. 120% 6% 405% 100% 3 150% 2.3%?
2. 1.2 0.8 0.007 0.453 0.0004 0.09?
3.0.75 75% 0.85 85% 0.3 30%?
Page 89 II. 1.√? 2.√ ? 3.╳ ? 4.√
Page 90 II. 1.75% 2.58% 3. 120% 4.97% 5.25%?
Page 9 1. 2.╳ ? 3.╳? 4.√
Page 92:1.125% 25% 2.20% 3.20% 4.4%?
Page 94 III. 1. 125% 2.25%?
Page 95 2. 1.20 million yuan. 895,900 yuan?
Page 96 II. 1.325 yuan 2. 17328 yuan 3. 6 1 57.95 yuan 4. 7650 yuan.
Page 97 2. 3 12 yuan 2. 80 yuan III. Ten percent off?
Page 98 2. 1 .20% discount 2. 33 yuan III. 32 137.7 yuan 4. 988 yuan?
Page 99 II, 1. 1600 2.30 Page 3. 640 4.5 12?
Page 100 III. 1. Desk 80 yuan Chair: 20 yuan 2. Wheat: 1000 square meters corn: 800 square meters?
3.( 1) Liu: 24 peaches: 96?
(2) Liu: 45 peaches: 75?
Page 10 1. (1)50 kg (2)30 kg 2. (1)90 copies (2) 160 copies?
3. Male: 8 10 Female: 648?
Page 102 II. 1.2.╳? 3.╳ ? 4.╳
Page 103 II. 1. Male: 24 Female: 30 RMB 2. 5 16.8 yuan 3. Male: 40 female: 80.
4.50 tons?
Extend the application?
Page 85 2 < (2.6) < 72 < (625)% (the answer is not unique)?
Page 86 is uncertain because the total number of students in two classes is unknown?
Page 87 (1) 541.5175% (2) 60%120.4?
Page 88 0.77 > 34 > 70% > 35 < 7.5%?
Page 89 (18+4)/(36+4) = 55%?
Page 90 200× 10% ÷ 5%-200 = 200 (g)?
Page 9 1 A: 70% B: 69% A good effect?
Page 92 2 ÷ (18+2) = 10%?
Page 9315-16 ÷16 = 20%?
Page 94 35 ÷ 23+45%- 1 = 300 (km)?
Page 95 5 ÷ (20%-15%) × (1-15%) = 85 (m)?
Page 96 800 ÷ 2 ÷ 5000 = 8%?
Page 97 (4000- 1000) ÷ 4000 = 75% This coat is sold at 25% off the original price?
On page 98, it's cost-effective to go to store C, because you have to pay 400 yuan to go to store A, so you have to get a shopping voucher of 100 yuan from the store; 320 yuan is needed to go to store B; You only need to pay 280 yuan to go to Store C.. ?
Page 99 0.5 ÷ (1-50%-25%) = 2 (meters)?
Page100 300 ÷ (50%-40%) = 3000 (m)?
Page101200 ÷ (1-20%)-200 = 50 (yuan)?
Page 102 5× 50-5× 50× 80% = 50 (yuan)?
Page 103 2× (1-13%) ← (1-70%) = 5.8 (kg)?
Unit exercise?
Second, 1. √? 2.╳? 3.╳? 4.╳? 5.╳
Three. 1.45% 1.52 0.438+0.230 20?
2.0.035 0.35% 0.0025 66.7% 62.5% 144.4% 0.06 175% 0.04
3.x = 10 x = 30 x = 0.25 x = 1.8 4。 9 19 96 15 1 5.( 1) 150 (2)64?
Four. 1. 10% 28400 yuan 3. 420 pieces of 4. (1) 270 (2) 22.5 (3) 505.450 yuan 6427.5 yuan.
6. 100 crayons and 60 watercolors in 7. 5,500 yuan 8. 125% 9.( 1)600 yuan (2) 135 yuan?
Seven, finishing and reviewing?
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Page 3 of 1 10, 1 .45161645 2.31unseen page 3.1234 2/.
Page 1 1 1 Page 2, 1. 2.╳ ? 3.√ ? 4.√
Page 1 13 2, 1. 2.√? 3.╳? 4.√
Page 1 16 2. 1.300ml 2。 Big box: 60 pairs of small boxes: 30 pairs of 3. 360 yuan?
Final exam?
Second, 1. √? 2.╳ 3.╳? 4.╳
Third, 1. C 2。 C 3。 A 4。 b？
Four. 1.32 17 1625 9 16 120 0 2449 36 14 2.32 14 14 57 2 13 0?
5.9 cm long and 3 cm wide?
Six, 1. (1) 23× 45 (2) 451-18 (3) 6×12× 35+32.20 people 3. 75%.
4. (1)1980m2 (2)3 000 m3 5. There are 325 students in the fourth grade and 390 students in the fifth grade.
6. 120 this 7. 35 yuan 8. Car B travels 50 kilometers per hour.
Important problem-solving methods in the sixth grade of primary school:?
First, fractional division solves the problem?
(Unknown unit "1") (divided by division): What fraction of the known unit "1"? Find the number of units "1". )
1, the relationship between quantity and fractional multiplication is the same.
(1) is the "de" before the score: the quantity of the unit "1" × the score = the quantity corresponding to the score.
(2) Before the score, it means "more or less": the quantity of unit "1" ×( 1 fraction) = the quantity corresponding to the score.
2. Solution: (Suggestion: It is best to solve by equation)
Equation (1): Let the unknown quantity be x according to the quantitative relation and solve it by equation.
(2) Arithmetic (division): the amount corresponding to the score ÷ the corresponding score = the amount of the unit "1".
3. Find the fraction of one number to another: just one number ÷ another number.
4. Find out how much one number is more (less) than another: the difference between two numbers ÷ unit "1" or:
① Find one more fraction: large number ÷ decimal number–1.
② Find decimals:1–decimals ÷ large numbers.
Second, fractional division.
1, the meaning of fractional division:
Multiplication: factor × factor = product division: product ÷ one factor = another factor.
Fractional division has the same meaning as integer division, which refers to the operation of knowing the product of two factors and one of them and finding the other factor.
2, the calculation rules of fractional division:
Dividing by a number that is not zero is equal to multiplying the reciprocal of this number.
Law (when fractional division is relatively large):
(1) When the divisor is greater than 1, the quotient is less than the dividend;
(2) When the divisor is less than 1 (not equal to 0), the quotient is greater than the dividend;
(3) When the divisor is equal to 1, the quotient is equal to the dividend.
""is called a bracket. In an equation, if there are both parentheses, you should count the parentheses first and then the parentheses.
Third, the ratio and the application of the ratio
(A), the meaning of the ratio
1, the meaning of ratio: the division of two numbers is also called the ratio of two numbers.
2. In the ratio of two numbers, the number before the comparison sign is called the first item of the ratio, and the number after the comparison sign is called the last item of the ratio. The quotient obtained by dividing the former term by the latter term is called the ratio.
For example,15:10 =15 ÷10 = 3/2 (the ratio is usually expressed as a fraction and can also be expressed as a decimal or an integer).
∶ ∶ ∶ ∶
The ratio of the former to the latter.
3. The ratio can represent the relationship between two identical quantities, that is, the multiple relationship. You can also use the ratio of two different quantities to represent a new quantity. For example: distance-speed = time.
4. Discrimination rate and ratio
Ratio: indicates the relationship between two numbers, which can be written in the form of ratio or fraction.
Ratio: equivalent to quotient, it is a number, which can be an integer, a fraction or a decimal.
According to the relationship between fraction and division, the ratio of two numbers can also be written as a fraction.
6, the relationship between ratio and division, fraction:
Compared with the previous ratio symbol ":",the latter ratio
Divider divisor divisor quotient
Fractional value of fractional dividing line "-"
7. The difference between ratio, division and fraction: except is an operation, fraction is a number, and ratio represents the relationship between two numbers.
8. According to the relationship between ratio and division and fraction, it can be understood that the latter term of ratio cannot be 0.
In the sports competition, the scores of the two teams are 2: 0, etc. This is just a form of scoring, which does not represent the division of two numbers.
(B) The basic nature of the ratio
1, according to the relation of ratio, division and fraction:
The property that the quotient is invariant: the dividend and divisor are multiplied or divided by the same number at the same time (except 0), and the quotient is invariant.
The basic property of a fraction: when the numerator and denominator of the fraction are multiplied or divided by the same number at the same time (except 0), the value of the fraction remains unchanged.
The basic nature of the ratio: the first and last items of the ratio are multiplied or divided by the same number at the same time (except 0), and the ratio remains unchanged.
2. The simplest integer ratio: the first and last terms of the ratio are integers and prime numbers, so this ratio is the simplest integer ratio.
3. According to the basic properties of the ratio, the ratio can be reduced to the simplest integer ratio.
4. Simplified ratio:
(2) Using the method of calculating the ratio. Note: The final result should be written in the form of ratio.
For example:15:10 =15 ÷10 = 3/2 = 3: 2.
5. Proportional allocation: allocate a quantity according to a certain proportion. This method is usually called proportional distribution.
If the ratio of two quantities is known, let these two quantities be.
The distance is fixed, and the speed ratio is inversely proportional to the time ratio. (For example, for the same distance, the speed ratio is 4: 5 and the time ratio is 5: 4).
The total amount of work is certain, and the work efficiency is inversely proportional to the working hours.
(For example, the total amount of work is the same, the working time ratio is 3: 2, and the working efficiency ratio is 2: 3)