【正文】 .......................................................................................................................8 二、 方法 ..................................................................................................................................................8 (一 ) 數(shù)的讀法和寫法 ..............................................................................................................................8 (二 ) 數(shù)的改寫 ..........................................................................................................................................9 (三 ) 數(shù)的互化 ........................................................................................................................................10 (四 ) 數(shù)的整除 ........................................................................................................................................11 (五 ) 約分和通分 ....................................................................................................................................11 三、 性質(zhì)和規(guī)律 ....................................................................................................................................11 (一 ) 商不變的規(guī)律 ................................................................................................................................11 (二 ) 小數(shù)的性質(zhì) ....................................................................................................................................11 (三 ) 小數(shù)點(diǎn)位置的移動(dòng)引起小數(shù)大小的變化 ....................................................................................11 (四 ) 分?jǐn)?shù)的基本性質(zhì) ............................................................................................................................12 (五 ) 分?jǐn)?shù)與除法的關(guān)系 ........................................................................................................................12 四、 運(yùn)算的意義 ....................................................................................................................................12 (一 ) 整數(shù)四則運(yùn)算 ................................................................................................................................12 (二 ) 小數(shù)四則運(yùn)算 ................................................................................................................................13 (三 ) 分?jǐn)?shù)四則運(yùn)算 ................................................................................................................................13 (四 ) 運(yùn)算定律 ........................................................................................................................................14 (五 ) 運(yùn)算法則 ........................................................................................................................................14 (六 ) 運(yùn)算順序 .....................................................................................................................................16 第二章 度量衡 ................................................................................................................................................16 一、 長(zhǎng)度 ................................................................................................................................................16 (一 ) 什么是長(zhǎng)度 ....................................................................................................................................16 (二 ) 長(zhǎng)度常用單位 ................................................................................................................................16 (三 ) 單位之間的換算 ............................................................................................................................17 二、 面積 ................................................................................................................................................17 (一 ) 什么是面積 .................................................................................................................................17 (二 ) 常用的面積單位 ............................................................................................................................17 專注于中小學(xué)教育 聯(lián)系電話： 18991890913 3 (三 ) 面積單位的換算 ............................................................................................................................17 三、 體積和容積 ....................................................................................................................................17 (一 ) 什么是體積、容積 ........................................................................................................................17 (二 ) 常用單位 ........................................................................................................................................17 (三 ) 單位換算 ........................................................................................................................................17 四、 質(zhì)量 ................................................................................................................................................18 (一 ) 什么是質(zhì)量 ....................................................................................................................................18 (二 ) 常用單位 ........................................................................................................................................18 (三 ) 常用換算 ........................................................................................................................................18 五、 時(shí)間 ................................................................................................................................................18 (一 ) 什么是時(shí)間 ....................................................................................................................................18 (二 ) 常用單位 ........................................................................................................................................18 (三 ) 單位換算