数学三年级下册思维导图
《数学三年级下册思维导图》
一、位置与方向 (Position and Direction)
1.1 方向辨别 (Direction Identification)
- 基本方向 (Basic Directions):
- 东 (East)
- 南 (South)
- 西 (West)
- 北 (North)
- 地图上的方向 (Direction on a Map):
- 上北下南,左西右东 (North at the Top, South at the Bottom, West on the Left, East on the Right)
- 描述方向 (Describing Directions):
- 东北 (Northeast)
- 东南 (Southeast)
- 西北 (Northwest)
- 西南 (Southwest)
- 实际应用 (Real-World Applications):
- 看地图找位置 (Finding Locations on a Map)
- 描述物体的位置 (Describing the Position of Objects)
- 指南针的使用 (Using a Compass)
1.2 简单的路线图 (Simple Route Maps)
- 识别路线图 (Identifying Route Maps):
- 起点 (Starting Point)
- 终点 (Ending Point)
- 途径地点 (Places Passed Through)
- 描述路线 (Describing Routes):
- 向东走 (Go East)
- 向南走 (Go South)
- 左转 (Turn Left)
- 右转 (Turn Right)
- 绘制简单的路线图 (Drawing Simple Route Maps):
- 标记地点 (Marking Locations)
- 用箭头表示方向 (Using Arrows to Indicate Direction)
- 简洁明了 (Concise and Clear)
二、除数是一位数的除法 (Division with a One-Digit Divisor)
2.1 口算除法 (Mental Division)
- 整十、整百数除以一位数 (Tens and Hundreds Divided by a One-Digit Number):
- 例如:60 ÷ 3 = 20, 800 ÷ 2 = 400
- 将被除数看作几个十或几个百 (Treat the Dividend as Several Tens or Several Hundreds)
- 估算除法 (Estimation in Division):
- 将除数或被除数近似成整十、整百数 (Approximate the Divisor or Dividend to Tens or Hundreds)
- 估计商的大致范围 (Estimate the Approximate Range of the Quotient)
2.2 笔算除法 (Written Division)
- 基本步骤 (Basic Steps):
- 从被除数的高位除起 (Start Dividing from the Highest Digit of the Dividend)
- 每次除得的商要写在对应的数位上 (Write the Quotient in the Corresponding Place Value)
- 余数必须比除数小 (The Remainder Must Be Smaller Than the Divisor)
- 没有余数的除法 (Division with No Remainder):
- 有余数的除法 (Division with a Remainder):
- 余数是除法运算的一部分 (The Remainder is Part of the Division Operation)
- 验算方法:商×除数+余数=被除数 (Verification Method: Quotient × Divisor + Remainder = Dividend)
- 商中间或末尾有0的除法 (Division with 0 in the Middle or at the End of the Quotient):
- 当某一位不够商1时,用0占位 (Use 0 as a Placeholder When a Digit is Not Enough for a Quotient of 1)
- 注意末尾0的写法 (Pay Attention to Writing the 0 at the End)
2.3 解决问题 (Problem Solving)
- 平均分问题 (Equal Distribution Problems):
- 将总数平均分成几份,求每份是多少 (Divide the Total Number into Several Equal Parts and Find the Number in Each Part)
- 包含除问题 (Grouping Problems):
- 求一个数里包含几个另一个数 (Find How Many of One Number are Contained in Another Number)
- 两步计算问题 (Two-Step Calculation Problems):
- 先算什么,再算什么 (What to Calculate First, and What to Calculate Second)
三、统计 (Statistics)
3.1 简单的数据分析 (Simple Data Analysis)
- 收集数据 (Collecting Data):
- 调查 (Surveys)
- 观察 (Observations)
- 记录 (Records)
- 整理数据 (Organizing Data):
- 分析数据 (Analyzing Data):
- 找出最大值、最小值 (Find the Maximum and Minimum Values)
- 计算总数 (Calculate the Total)
- 发现规律 (Discover Patterns)
3.2 平均数 (Average)
- 平均数的意义 (Meaning of Average):
- 代表一组数据的平均水平 (Represents the Average Level of a Set of Data)
- 平均数的计算方法 (Calculation Method of Average):
- 总数÷份数=平均数 (Total Number ÷ Number of Parts = Average)
- 平均数的应用 (Application of Average):
- 比较不同组数据的平均水平 (Compare the Average Level of Different Groups of Data)
- 解决实际问题 (Solve Practical Problems)
四、年、月、日 (Year, Month, Day)
4.1 时间单位 (Units of Time)
- 年 (Year):
- 平年 (Common Year): 365天 (365 Days)
- 闰年 (Leap Year): 366天 (366 Days)
- 判断闰年:年份能被4整除,但不能被100整除;或者能被400整除 (Judging Leap Years: A Year is Divisible by 4 but not by 100; or Divisible by 400)
- 月 (Month):
- 大月 (Large Month): 31天 (31 Days) (1, 3, 5, 7, 8, 10, 12 月)
- 小月 (Small Month): 30天 (30 Days) (4, 6, 9, 11 月)
- 二月 (February): 平年28天 (28 Days in a Common Year), 闰年29天 (29 Days in a Leap Year)
- 日 (Day):
4.2 时间的计算 (Time Calculation)
- 计算经过的时间 (Calculating Elapsed Time):
- 开始时间 (Start Time)
- 结束时间 (End Time)
- 用结束时间减去开始时间 (Subtract the Start Time from the End Time)
- 解决时间问题 (Solving Time Problems):
- 合理安排时间 (Arranging Time Reasonably)
五、两位数乘两位数 (Multiplication of Two-Digit Numbers)
5.1 口算乘法 (Mental Multiplication)
- 整十数乘整十数 (Tens Times Tens):
- 例如:20 × 30 = 600
- 将两个数看作几个十相乘 (Treat the Two Numbers as Several Tens Multiplied Together)
5.2 笔算乘法 (Written Multiplication)
- 基本步骤 (Basic Steps):
- 用第二个乘数的个位与第一个乘数的每一位分别相乘 (Multiply Each Digit of the First Multiplier by the Ones Digit of the Second Multiplier)
- 用第二个乘数的十位与第一个乘数的每一位分别相乘 (Multiply Each Digit of the First Multiplier by the Tens Digit of the Second Multiplier)
- 将两次乘得的积相加 (Add the Two Products Together)
- 进位 (Carrying):
- 注意进位的处理 (Pay Attention to Handling the Carry-Over)
- 0的乘法 (Multiplication by 0):
- 任何数与0相乘都得0 (Any Number Multiplied by 0 Equals 0)
5.3 解决问题 (Problem Solving)
- 总价问题 (Total Price Problems):
- 单价×数量=总价 (Unit Price × Quantity = Total Price)
- 面积问题 (Area Problems):
- 长方形面积=长×宽 (Area of a Rectangle = Length × Width)
- 正方形面积=边长×边长 (Area of a Square = Side Length × Side Length)
六、面积 (Area)
6.1 面积的认识 (Understanding Area)
- 面积的意义 (Meaning of Area):
- 物体表面或封闭图形的大小 (The Size of an Object's Surface or a Closed Figure)
- 常用的面积单位 (Commonly Used Units of Area):
- 平方厘米 (Square Centimeter) (cm²)
- 平方分米 (Square Decimeter) (dm²)
- 平方米 (Square Meter) (m²)
- 面积单位之间的进率 (Conversion Rates Between Area Units):
- 1平方米=100平方分米 (1 m² = 100 dm²)
- 1平方分米=100平方厘米 (1 dm² = 100 cm²)
6.2 面积的计算 (Area Calculation)
- 长方形面积的计算 (Calculation of the Area of a Rectangle):
- 面积=长×宽 (Area = Length × Width)
- 正方形面积的计算 (Calculation of the Area of a Square):
- 面积=边长×边长 (Area = Side Length × Side Length)
- 不规则图形的面积估算 (Estimating the Area of Irregular Shapes):
- 用方格纸进行估算 (Estimating with Grid Paper)
6.3 面积单位的应用 (Application of Area Units)
- 测量物体表面 (Measuring the Surface of Objects)
- 计算房间面积 (Calculating the Area of a Room)
- 估计操场面积 (Estimating the Area of a Playground)
七、小数的初步认识 (Preliminary Understanding of Decimals)
7.1 小数的读法和写法 (Reading and Writing Decimals)
- 小数的组成 (Composition of Decimals):
- 整数部分 (Integer Part)
- 小数点 (Decimal Point)
- 小数部分 (Decimal Part)
- 小数的读法 (Reading Decimals):
- 整数部分按整数的读法读 (Read the Integer Part as an Integer)
- 小数点读作“点” (Read the Decimal Point as "Point")
- 小数部分依次读出每一位上的数字 (Read Each Digit in the Decimal Part in Order)
- 小数的写法 (Writing Decimals):
- 先写整数部分 (Write the Integer Part First)
- 再写小数点 (Then Write the Decimal Point)
- 最后写小数部分 (Finally Write the Decimal Part)
7.2 小数的大小比较 (Comparing the Size of Decimals)
- 先比较整数部分 (First Compare the Integer Parts):
- 整数部分大的数就大 (The Number with the Larger Integer Part is Larger)
- 整数部分相同,比较小数部分 (If the Integer Parts are the Same, Compare the Decimal Parts):
- 从十分位开始比较,依次比较 (Compare from the Tenths Place and Compare in Order)
7.3 简单的小数加减法 (Simple Addition and Subtraction of Decimals)
- 小数点对齐 (Align the Decimal Points):
- 整数部分和整数部分对齐 (Align the Integer Parts)
- 小数部分和小数部分对齐 (Align the Decimal Parts)
- 按整数加减法计算 (Calculate as Integer Addition and Subtraction)
- 结果也要对齐小数点 (Align the Decimal Point in the Result)
八、数学广角——搭配(二) (Mathematical Corner - Arrangement (II))
8.1 简单的排列组合 (Simple Permutations and Combinations)
- 排列 (Permutations):
- 按一定的顺序排列 (Arrange in a Certain Order)
- 交换顺序会产生不同的结果 (Changing the Order Will Produce Different Results)
- 组合 (Combinations):
- 不考虑顺序 (Order is Not Considered)
- 交换顺序不影响结果 (Changing the Order Does Not Affect the Result)
- 列表法 (Listing Method):
- 列出所有可能的排列或组合 (List All Possible Permutations or Combinations)
- 连线法 (Line Connection Method):
- 用连线的方式表示搭配 (Represent Matching by Connecting Lines)
8.2 解决实际问题 (Solving Practical Problems)
- 合理分析问题 (Analyzing Problems Rationally)
- 运用排列组合的知识 (Applying Knowledge of Permutations and Combinations)
- 寻找规律,简化计算 (Finding Patterns to Simplify Calculations)