讲错题（打×的题）。要求：深入浅出，·幽默风趣，适合小学三年级学生---**General Information** * **Title/Concept Explanation:** 周长和面积是两个不同 的概念,所表示的意义也不同。周长是指物体所占平面的大小,二者不能混淆。 * *(Translation: Perimeter and area are two different concepts, and their meanings are different. Perimeter refers to the length of the boundary of an object, while area refers to the size of the plane occupied by the object. The two cannot be confused.)* * **Section Title:** 选择题 * *(Translation: Multiple Choice Questions)* --- **Question 1** * **Question Stem:** 1. 选一选。(将正确答案的序号填在括号里) * *(Translation: 1. Choose. (Fill the number of the correct answer in the parentheses))* * **Sub-question (1):** 刘大叔靠墙搭围墙一块菜地(如图),他要给菜地盖上塑料薄膜, 篱笆长是( )米,覆盖塑料薄膜的面积至少是( )平方米。 * *(Translation: Uncle Liu built a fence against a wall for a vegetable patch (as shown in the figure). He wants to cover the vegetable patch with plastic film. The length of the fence is ( ) meters, and the area covered by the plastic film is at least ( ) square meters.)* * **Chart Description:** * **Type:** Geometric figure (rectangle with one side designated as a wall). * **Main Elements:** A rectangle. * **Labels:** One side is labeled "8米" (8 meters), and an adjacent side is labeled "6米" (6 meters). An arrow points to the longer side (8m) indicating it is the side against the wall. * **Relative Position:** The figure depicts a rectangular area, with one of its longer sides (8m) adjacent to a "墙" (wall). * **Options:** * (1) 20米 * (2) 48米 * (3) 48平方米 * **Sub-question (2):** 王叔叔每天早上绕着公园正方形的花坛跑 5 圈,正好是 800 米。 这个正方形花坛的面积是( )平方米。 * *(Translation: Uncle Wang runs 5 laps around the square flower bed in the park every morning, which is exactly 800 meters. The area of this square flower bed is ( ) square meters.)* * **Options:** * (1) 120 * (2) 160 * (3) 1600 * **Sub-question (3):** 学校长方形的操场原来长 120 米,宽 90 米,扩建后,长和宽各 增加了 20 米,扩建后的操场面积是( )平方米。 * *(Translation: The school's rectangular playground was originally 120 meters long and 90 meters wide. After expansion, the length and width each increased by 20 meters. What is the area of the playground after expansion ( ) square meters.)* * **Options:** * (1) 10800 * (2) 12600 * (3) 15400 --- **Question 2** * **Question Stem:** 2. 一个正方形和一个长方形的周长相等,长方形的长是 25 厘米,宽是 13 厘米,正方形的面积是多少平方厘米? * *(Translation: 2. The perimeter of a square and a rectangle are equal. The length of the rectangle is 25 cm, and the width is 13 cm. What is the area of the square in square centimeters?)* * **Handwritten Notes/Solution:** * Calculation: 25 × 13 = 325 cm² * Answer statement: 答: 是 325 cm² * *(Translation: Answer: It is 325 cm²)* --- **Partially Visible Content (from other questions/context, top left of image)** * **Text:** * 20米 * 10米 * 周长 * 计划用砖铺一个厨房的地面。厨房长5米,宽3米, 如果选择下面两种设计方案,分别需要多少钱? * *(Translation: Plan to pave a kitchen floor with bricks. The kitchen is 5 meters long and 3 meters wide. If you choose one of the following two design plans, how much will it cost?)* * 方案二: * *(Translation: Plan two:)* * 3分米 * 每块2元 * *(Translation: 2 yuan per piece)* * 6分米 * 每块4元 * *(Translation: 4 yuan per piece)* * 2分米 * 丁 225 块地砖,这个厨房的面积是 多少平方米? * *(Translation: 225 floor tiles. What is the area of this kitchen in square meters?)* * 地砖? * *(Translation: floor tile?)* * **Mathematical/Unit Conversion (partially obscured):** * `-> m` (arrow indicating conversion to meters) * `1块 = 9 m²` (or `dm²` - unit is slightly obscured but likely dm²) * `-> m²` (arrow indicating conversion to square meters) Here is the extracted content from the image: --- **General Information/Header:** * 三、年级下 (Third Grade, Lower Semester) * 长方形和正方形的面积的应 (Application of the Area of Rectangles and Squares) --- **Question 1:** **Instruction:** 1. 选一选。(将正确答案序号填在括号里) (1. Choose one. (Fill in the number of the correct answer in the parentheses)) **Part (1):** * **Question Stem:** 淘淘家客厅的长方形地面长5米，宽3米。用面积是1平方米的正方形地砖铺客厅，需要（ ）块。 (Taotao's living room has a rectangular floor 5 meters long and 3 meters wide. How many 1-square-meter square tiles are needed to cover the living room?) * **Options:** * ① 300 * ② 375 * ③ 200 * **Handwritten Annotations:** A handwritten '1' is written in the blank space for the answer, and it is circled. A handwritten 'X' mark is placed next to option ③. **Part (2):** * **Question Stem:** 王叔叔用边长4分米的正方形地砖铺客厅的长方形地面。沿着客厅的长正好铺了15块，沿着客厅的宽正好铺了10块。客厅的面积是（ ） (Uncle Wang uses square tiles with a side length of 4 decimeters to pave the rectangular floor of the living room. Along the length of the living room, exactly 15 tiles are laid, and along the width, exactly 10 tiles are laid. The area of the living room is ( )) * **Options:** * ① 600 平方分米 (600 square decimeters) * ② 24 平方米 (24 square meters) * ③ 15 平方米 (15 square meters) * **Handwritten Annotations:** A handwritten '1' is written in the blank space for the answer, and it is circled. A handwritten 'X' mark is placed over option ①. --- **Question 2:** **Instruction:** 2. 下面的解法对吗？如果不对，请改正过来。 (Is the following solution correct? If not, please correct it.) **Part (1):** * **Question Stem:** 一张长方形彩纸长18厘米，宽12厘米。这张彩纸的面积是多少平方厘米？ (A rectangular colored paper is 18 centimeters long and 12 centimeters wide. What is the area of this colored paper in square centimeters?) * **Chart/Diagram Description:** * **Type:** A cartoon illustration with a speech bubble. * **Main Elements:** * A drawing of a boy in a simple, energetic pose, looking towards the right. * A speech bubble originating from the boy's head. * **Text within Speech Bubble:** 我的解法： (My solution:) * **Proposed Solution (Text):** (18+12)×2=60 (平方厘米) ( (18+12)×2=60 (square centimeters) ) * **Proposed Answer (Text):** 答：这张彩纸的面积是60平方厘米。 (Answer: The area of this colored paper is 60 square centimeters.) * **Handwritten Annotations (Correction):** * Red handwritten text: 你不对 (You are wrong) * A large red 'X' is drawn over the proposed solution and answer. * Red handwritten corrected calculation: 18×12=216cm² (18 * 12 = 216 square centimeters) --- **Other Relevant Text / Miscellaneous Handwritten Notes (Top Left Corner):** * 播种的宽度 = 每分钟播种的面积 (Sowing width = area sown per minute) * 播种机每小时可播种1500米, 播种的宽度是2米。播种机每 (Sowing machine can sow 1500 meters per hour, the sowing width is 2 meters. Sowing machine per...) - *Incomplete sentence.* * 播种的面积是多少平方分米？ (What is the area sown in square decimeters?) * 单位间的进率 (Conversion rate between units) * =4000dm² * 200dm² (with an 'X' over it) * 4800dm² * 以及相同6块小玻璃，每块小玻 (And 6 identical small pieces of glass, each small piece of glass) - *Incomplete sentence.* **Global Headers:** * 同步小侦探 (Synchronous Little Detective) * 面积周长天天练 (Area Perimeter Daily Practice) * 长方形和正方形 (Rectangles and Squares) * 三年级下R (Grade 3 Lower R) --- **Question 1 (Left Page - Area/Perimeter Daily Practice)** **Question Stem:** 有一台播种机，每分钟行驶80米，播种的宽度是2米。播种机3分钟可以播多少平方米的地面？ (There is a sowing machine. It travels 80 meters per minute, and the sowing width is 2 meters. How many square meters of land can the sowing machine sow in 3 minutes?) **Other Relevant Text (Handwritten Calculations/Annotations):** * 每分钟行驶的距离 × 播种的宽度 = 每分钟播种的面积 (Distance traveled per minute × sowing width = Area sown per minute) * 80×2=160 m² * 160×3=480 m² * 答：480 m² (Answer: 480 square meters) - This answer is circled. --- **Question 2 (Left Page - Area/Perimeter Daily Practice)** **Question Stem:** 把边长3米的正方形玻璃切割成大小相同的6块小玻璃，每块小玻璃的面积是多少平方分米？ (Cut a square glass with side length 3 meters into 6 small pieces of the same size. What is the area of each small piece of glass in square decimeters?) **Other Relevant Text (Handwritten Calculations/Annotations):** * 3×3=9 m² * 9 m² = 900 dm² * 900÷6=150 dm² * 答：150 dm² (Answer: 150 square decimeters) - This answer is circled. --- **Question 3 (Left Page - Area/Perimeter Daily Practice)** **Question Stem (Partially visible):** 3. 好日子酒店要在门口宽4米的台阶上铺红地毯（如... (The rest is cut off) (3. Good Day Hotel wants to lay a red carpet on the 4-meter wide steps at the entrance (as shown in...) **Other Relevant Text (Handwritten Calculations/Annotations - Partially visible and potentially incorrect):** * 3×4=12 m * 22÷6=? (Incomplete calculation) * 22×6=200 dm² (Crossed out) * 答：100 dm² (Crossed out) * 2+4×5=30m² (Partially visible, unclear context) --- **Question 1 (Right Page - Multiple Choice)** **Question Stem:** 1. 选一选。(将正确答案的序号填在括号里) (1. Choose. (Fill in the serial number of the correct answer in the parentheses)) **Sub-questions and Options:** (1) 淘淘家书房的长方形地板，长方形地砖的面积是 ( ) 平方厘米。 (Tao Tao's study has rectangular floor tiles. The area of the rectangular tiles is ( ) square centimeters.) * (Options are not fully visible. Only the first option is partially visible.) * Option ①: 600 平方分米 (600 square decimeters) - This option is crossed out with an 'X'. (2) 王叔叔用边长4分米，正好铺了15块。客厅的长正好铺了15块，客厅的面积是 ( ) (Uncle Wang used tiles with side length 4 decimeters, exactly covering 15 pieces. The length of the living room exactly fits 15 pieces. The area of the living room is ( )) * Option ①: 300 - This option is circled. * Option ②: 600 平方分米 (600 square decimeters) - This option is crossed out with an 'X'. --- **Question 2 (Right Page)** **Question Stem:** 2. 下面的解法对吗？如果不对，请改正。 (2. Is the following solution correct? If not, please correct it.) **Sub-question (Partially visible):** (1) 一张长方形彩纸长... (The rest is cut off) (1) A rectangular colored paper is long... **Other Relevant Text (Annotations/Labels):** * 我的解法：(My solution:) - Label next to a cartoon character. * 答：不对 (Answer: Incorrect) - Label next to another cartoon character. * 我的解法：(My solution:) - Label next to a third cartoon character. * 时尚大帝 HONNY TONNY (Fashion Emperor HONNY TONNY) - Label on a pink bookmark-like object. **Page Number:** 28 --- **Question 3:** * **Question Stem:** 一根铁丝可以围成一个边长60厘米的正方形。现在把它改围成一个长80厘米的长方形，这个长方形的面积是多少平方厘米？ (Translation: A wire can form a square with a side length of 60 centimeters. If it is now reshaped into a rectangle with a length of 80 centimeters, what is the area of this rectangle in square centimeters?) * **Student's Calculations and Solution:** 周长 60 × 4 = 240 (cm) 长 80 cm 宽 240 ÷ 2 - 80 = 120 - 80 = 40 (cm) 面积 80 × 40 = 3200 (cm²) 答：面积是3200cm² --- **Question related to Grid/Chart:** * **Partial Question Text:** 长是1分米. 图甲 A B是16dm² (The '16dm²' part has a strikethrough, followed by another 'B是16dm²' without a strikethrough, and a red line pointing to area B) * **Chart Description:** * **Type:** Grid/Graph with labeled areas. * **Main Elements:** * A grid of small squares. * Two distinct shaded or outlined areas labeled 'A' and 'B'. * **Area A:** An L-shaped region composed of small squares. Visually, it covers 12 small squares (e.g., a 4x4 square with a 2x2 square removed from one corner). * **Area B:** A rectangular (specifically, square) region composed of small squares. Visually, it covers 4 small squares (e.g., a 2x2 square). * **Labels/Annotations:** * "A" labels the L-shaped area. * "B" labels the 2x2 square area. * Handwritten text near the grid: "长是1分米." (Length is 1 decimeter.) * Handwritten text near the grid, next to 'B': "B是16dm²". This text is written twice; the first instance of "16dm²" is crossed out. A red line points from this text to Area B. --- **Question 7 (Partially visible):** * **Partial Question Stem:** 7. 一个长方形... (Translation: 7. A rectangle...) * **Student's Calculations/Notes (related to Q7 or previous problems):** 20 x 4 = 80 x 60 10米,宽增加 (Translation: 10 meters, width increased) **Extracted Content:** **General Information / Page Header:** * **Title:** 连乘、连除解决问题易错练 (Consecutive Multiplication, Consecutive Division Problem Solving Common Mistakes Practice) * **Grade Level:** 三年级 (Third Grade) --- **Question 2:** * **Question Stem:** (Partial) "...火车票售价321元, 3人往返一共需要多少元?" (The beginning of the sentence is cut off. It asks: "The train ticket costs 321 yuan, how much does it cost in total for 3 people to travel round trip?") * **Options:** * ① (Content is mostly cut off, only the option number is clearly visible). * ② 321 × (3 + 2) * ③ 321 × 3 × 2 --- **Question 3:** * **Question Stem:** 3. 豆腐是一种营养丰富且历史悠久的食材。某豆腐店有 3 袋黄豆，每袋 25 千克。如果 1 千克黄豆能做成 4 千克豆腐，这批黄豆能做多少千克豆腐？ (Translation: Tofu is a nutritious and historical ingredient. A tofu shop has 3 bags of soybeans, each weighing 25 kilograms. If 1 kilogram of soybeans can make 4 kilograms of tofu, how many kilograms of tofu can this batch of soybeans make?) * **Handwritten Solution/Annotation:** * Calculation: 3 × 25 × 4 = 75 × 4 = 300 (千克) * Answer: 答: 300千克 (Answer: 300 kg) --- **Question 4:** * **Fragmented Question Stem (Partial and potentially from another problem):** (This appears below the options for Question 2 and before the complete Question 4) "...期 (7 天) 吃了 168 千克萝卜。平均每..." (...period (7 days) ate 168 kilograms of radish. On average, per...) * **Complete Question Stem:** 叔叔家种了 5 行苹果树，每行 5 棵。今年平均每棵收获苹果 32 千克。叔叔家今年一共能收获苹果多少千克？ (Translation: Uncle's family planted 5 rows of apple trees, with 5 trees in each row. This year, each tree harvested an average of 32 kilograms of apples. How many kilograms of apples did Uncle's family harvest in total this year?) * **Handwritten Solution/Annotation:** * Calculation: 5 × 5 × 32 = 25 × 32 = 800 (千克) --- **Other Handwritten Calculations (Context unclear for these specific calculations):** * 72 × 4 = 288 (元) * 答: 288元 (Answer: 288 Yuan) **Non-Question Information:** * **Header/Logo:** * 黄冈小状元 (Huanggang Little Champion) * 解决问题天天练 (Daily Practice for Problem Solving) * 进位笔算乘法 (Carrying over vertical multiplication) * 三年级下(R) (Grade Three, Lower Semester (R)) * **Text on Wooden Stand:** * 绵阳市安州区交通运输局 (Mianyang Anzhou District Transportation Bureau) * 绵阳明星运输服务有限公司 (Mianyang Mingxing Transportation Service Co., Ltd.) * TEL:0816-4563329 --- **Question 1 (Left Page):** * **Question Stem:** 1. 同学们还记得《曹冲称象》的故事吗？如果称一头小象用去了48块石头，平均每块石头重32千克，这头小象重多少千克？ * _Translation_: Do you still remember the story of "Cao Chong weighing the elephant"? If it took 48 stones to weigh a small elephant, and each stone weighs an average of 32 kilograms, how many kilograms does this small elephant weigh? * **Handwritten Calculation:** 48 × 32 = 576 (千克) * **Handwritten Answer:** 答: 576千克。 * **Chart/Diagram Description:** * **Type:** Line drawing illustration. * **Main Elements:** The illustration depicts a scene from the "Cao Chong Weighing the Elephant" story. * An elephant is standing in a boat, which is floating on a body of water. * A person (presumably Cao Chong) is kneeling or sitting on the bank next to the boat, seemingly observing or interacting with a pile of stones. * Several stones are drawn on the bank. * The boat has a distinct waterline mark, indicating the level it sinks to in the water. --- **Question 1 (Right Page - Incomplete):** * **Question Stem:** 1. 选一选。(将正确答案的序号填在括号里) * _Translation_: Choose one. (Fill in the serial number of the correct answer in the parentheses) * **(1) Part 1:** * 为了保护... (To protect...) * 每吨水 3 元 (3 yuan per ton of water) * (...)。 [A handwritten '3' is present within the parentheses, circled and crossed out with a red 'X'.] * **Options for (1) Part 1:** * ① 3 × 5 [A red line is drawn from this option to the right.] * **(2) Part 1:** * 希望小... (Hope small...) * 玻璃。这... (glass. This...) * 是 (...) [A handwritten '3' is present within the parentheses, circled.] * **Options for (2) Part 1:** * ① 一共有 (There are a total of) --- **Question 2 (Left Page):** * **Question Stem:** 2. 选一选。(将正确答案的序号填在括号里) * _Translation_: Choose one. (Fill in the serial number of the correct answer in the parentheses) * **(1):** * 张经理和 16 位同事去吃早餐，每人吃了一碗 18 元的牛肉面。结账时，老板给每人优惠了 2 元，他们一共要付 (...) 元。 * _Translation_: Manager Zhang and 16 colleagues went for breakfast. Each person ate a bowl of 18 yuan beef noodles. When checking out, the boss gave a discount of 2 yuan per person. How much did they have to pay in total? * **Options for 2.(1):** * ① 256 * ② 320 * ③ 272 [A handwritten '1' is present within the parentheses next to the question, circled and crossed out with a red 'X', suggesting it was the student's incorrect answer or choice.] * **Question Stem (2):** * 淘淘家离学校 2 千米，他从家出发步行去学校，平均每分钟步行 65 米，离家 14 分钟后正好经过壮壮家。壮壮家离学校 (...) 米。 * _Translation_: Taotao's home is 2 kilometers from school. He walks from home to school, averaging 65 meters per minute. After 14 minutes of walking from home, he just passes Zhuangzhuang's home. How many meters is Zhuangzhuang's home from school? --- **Question 2 (Right Page - Incomplete):** * **Question Stem:** 2. 药店新运... (Pharmacy newly transported...) 多少个？ (How many?)