一：數字不是孤立的46Please respect copyright.ＰＥＮＡＮＡlGKJ5f81dt
上一課我們學了數線：46Please respect copyright.ＰＥＮＡＮＡZWrMkhAU74
> 0 —— 1 —— 2 —— 3 —— 4 —— 546Please respect copyright.ＰＥＮＡＮＡJ5azJzOlzL
每一個數都有位置。
今課我們不只看一個數在哪裏，而是看：46Please respect copyright.ＰＥＮＡＮＡkhsw2lIjev
> 它的旁邊是甚麼數？46Please respect copyright.ＰＥＮＡＮＡrumnnv8J1U
例如：46Please respect copyright.ＰＥＮＡＮＡdEUeovVAQn
> 3 的右邊是 446Please respect copyright.ＰＥＮＡＮＡ0uV5zkeRJj
> 3 的左邊是 246Please respect copyright.ＰＥＮＡＮＡvyEoXof9lY
所以可以講：46Please respect copyright.ＰＥＮＡＮＡmArbnXz7AK
> 4 比 3 多一46Please respect copyright.ＰＥＮＡＮＡNHUettRfN5
> 2 比 3 少一46Please respect copyright.ＰＥＮＡＮＡROiuBNb0zC
今日的核心就係：46Please respect copyright.ＰＥＮＡＮＡHYkQc5G9l4
> 多一 | One More46Please respect copyright.ＰＥＮＡＮＡo5bltPUBs5
> 少一 | One Less46Please respect copyright.ＰＥＮＡＮＡdAAuSAD3o3
二：多一是甚麼？46Please respect copyright.ＰＥＮＡＮＡbKc1BhqSSr
如果你有 3 粒糖果：46Please respect copyright.ＰＥＮＡＮＡ2Dgi4qIzj5
> 🍬🍬🍬46Please respect copyright.ＰＥＮＡＮＡUwx31fOz15
再多 1 粒：46Please respect copyright.ＰＥＮＡＮＡbOP95WYB0x
> 🍬🍬🍬🍬46Please respect copyright.ＰＥＮＡＮＡpU5Eni03an
就變成 4 粒。
所以：46Please respect copyright.ＰＥＮＡＮＡjDeKBNWJ9g
> 3 多一是 4
用數線看：46Please respect copyright.ＰＥＮＡＮＡHy2gWdQEV2
> 0 —— 1 —— 2 —— 3 —— 4 —— 546Please respect copyright.ＰＥＮＡＮＡRsFJJP5KZE
> 3 → 446Please respect copyright.ＰＥＮＡＮＡWmaQAI4y2s
由 3 向右行一格，就去到 4。
所以：46Please respect copyright.ＰＥＮＡＮＡa3KXCGds65
> 多一 = 數線上向右行路
三：少一是甚麼？
如果你有 3 粒糖果：46Please respect copyright.ＰＥＮＡＮＡCNWk82aDit
> 🍬🍬🍬46Please respect copyright.ＰＥＮＡＮＡAtnBJQgS5Q
少了 1 粒：46Please respect copyright.ＰＥＮＡＮＡMI9go7yJeH
> 🍬🍬46Please respect copyright.ＰＥＮＡＮＡlDrJzgfuwZ
就變成 2 粒。
所以：46Please respect copyright.ＰＥＮＡＮＡ4wXS2nGKF5
> 3 少一是我
用數線看：46Please respect copyright.ＰＥＮＡＮＡQ2Qt2XktP9
> 0 —— 1 —— 2 —— 3 —— 4 —— 546Please respect copyright.ＰＥＮＡＮＡYWgUa7tQ8g
> 2 ← 346Please respect copyright.ＰＥＮＡＮＡ3JYZnShEJr
由 3 向左行一格，就去到 2。
所以：46Please respect copyright.ＰＥＮＡＮＡzdy1QgGrAo
> 少一 = 數線上向左行一格46Please respect copyright.ＰＥＮＡＮＡxv1IDfzq1q
四：後繼數與前一個數
數學入面有兩個有用的詞語。
1. 後繼數 | Successor
一個數的後繼數，就是它右邊下一個數。
例如：46Please respect copyright.ＰＥＮＡＮＡPwbesSmooN
> 2 的後繼數是 346Please respect copyright.ＰＥＮＡＮＡMNcjDwL79Q
> 5 的後繼數是 646Please respect copyright.ＰＥＮＡＮＡUiVacnChM7
> 9 的後繼數是 1046Please respect copyright.ＰＥＮＡＮＡZ0cONkeSzp
//
2. 前一個數 | Predecessor46Please respect copyright.ＰＥＮＡＮＡBNG5MUj031
一個數的前一個數，就是它左邊上一個數。
例如：46Please respect copyright.ＰＥＮＡＮＡKWDjZTMJaC
> 4 的前一個數是 346Please respect copyright.ＰＥＮＡＮＡX8c0G7zzju
> 8 的前一個數是 746Please respect copyright.ＰＥＮＡＮＡeMqkPWaudN
> 10 的前一個數是 946Please respect copyright.ＰＥＮＡＮＡ90SXxS7ZGz
五：簡單例子46Please respect copyright.ＰＥＮＡＮＡRem2FnQL11
例子 1：5 多一是幾多？46Please respect copyright.ＰＥＮＡＮＡAlvNkLCHG8
用數線：46Please respect copyright.ＰＥＮＡＮＡfJZy1fM68R
> 0 —— 1 —— 2 —— 3 —— 4 —— 5 —— 646Please respect copyright.ＰＥＮＡＮＡ3B7Onq39zm
由 5 向右行一格：46Please respect copyright.ＰＥＮＡＮＡHrUGFWV9k0
> 5 → 646Please respect copyright.ＰＥＮＡＮＡDGL608ig1B
所以：46Please respect copyright.ＰＥＮＡＮＡPPQV7pZ6Cl
> 5 多一是 646Please respect copyright.ＰＥＮＡＮＡKN0ZjDaZtw
//
例子 2：5 少一是幾多？46Please respect copyright.ＰＥＮＡＮＡfQliEm8pLv
由 5 向左行一格：46Please respect copyright.ＰＥＮＡＮＡ15ZE8K9wwn
> 4 ← 546Please respect copyright.ＰＥＮＡＮＡZprO13klhw
所以：46Please respect copyright.ＰＥＮＡＮＡ3THhmLzvgq
> 5 少一是 446Please respect copyright.ＰＥＮＡＮＡEjiKpfuD9P
//
例子 3：0 多一是幾多？
由 0 向右行一格：46Please respect copyright.ＰＥＮＡＮＡ4k89dxmOKL
> 0 → 146Please respect copyright.ＰＥＮＡＮＡhkntVDvI5c
所以：46Please respect copyright.ＰＥＮＡＮＡzeH6AM8mec
> 0 多一是 146Please respect copyright.ＰＥＮＡＮＡ6yXEqU3dlJ
意思：46Please respect copyright.ＰＥＮＡＮＡImnnMrnVk5
> 由沒有任何一個，變成有一個。46Please respect copyright.ＰＥＮＡＮＡIzzQTgv4D0
六：0 可不可以少一？46Please respect copyright.ＰＥＮＡＮＡntI43Ln9fa
現在我們的數線：46Please respect copyright.ＰＥＮＡＮＡBYU44BU9Ku
> 0 —— 1 —— 2 —— 3 —— 446Please respect copyright.ＰＥＮＡＮＡiDWb1HDMDe
問題：46Please respect copyright.ＰＥＮＡＮＡwB0evDeDI5
> 0 少一是幾多？46Please respect copyright.ＰＥＮＡＮＡJP5WqQy0Vx
如果只講「物件數量」，0 已經代表沒有任何一件。
那麼「少一」就好像在問：46Please respect copyright.ＰＥＮＡＮＡy7j1N5yhc2
> 沒有粒糖，再少一粒糖果，會變成如何？46Please respect copyright.ＰＥＮＡＮＡROzR5F9BQm
在目前的數量世界入面，答案是：46Please respect copyright.ＰＥＮＡＮＡB9tmKbPpeT
> 做不到。46Please respect copyright.ＰＥＮＡＮＡ5ZivPav8qN
因為你沒有糖果可以再拎走。
所以在現在這個階段：46Please respect copyright.ＰＥＮＡＮＡkRpQjVqGjE
> 0 沒有前一個自然數。46Please respect copyright.ＰＥＮＡＮＡrOy2Q7IRrq
將來學習負數時，我們會擴展數線：46Please respect copyright.ＰＥＮＡＮＡsxwJ71yF1T
> -1 —— 0 —— 1 —— 246Please respect copyright.ＰＥＮＡＮＡpGTRZHhgyj
那時 0 少一就會是：46Please respect copyright.ＰＥＮＡＮＡCOIXdicg5f
> -146Please respect copyright.ＰＥＮＡＮＡxmypd7Ysyq
七：多一和少一是相反方向46Please respect copyright.ＰＥＮＡＮＡBdEEFzOMqN
如果由 3 多一：46Please respect copyright.ＰＥＮＡＮＡVDSwUiSYEh
> 3 → 446Please respect copyright.ＰＥＮＡＮＡ4EqhHVFnOb
再少一：46Please respect copyright.ＰＥＮＡＮＡfi8PodD3n6
> 4 → 346Please respect copyright.ＰＥＮＡＮＡsNZsgnHq6a
就返到原本的 3。
相反，如果由 3 少一：46Please respect copyright.ＰＥＮＡＮＡPufzXo08IJ
> 3 → 246Please respect copyright.ＰＥＮＡＮＡmYO56lv1Ha
再多一：46Please respect copyright.ＰＥＮＡＮＡQHzuFHBYuT
> 2 → 346Please respect copyright.ＰＥＮＡＮＡ1vllJsX7y3
都返到原本的 3。
所以：46Please respect copyright.ＰＥＮＡＮＡBFnBXI4Ccw
> 多一和少一是相反動作。46Please respect copyright.ＰＥＮＡＮＡUiNRhrRvFv
八：連續多一46Please respect copyright.ＰＥＮＡＮＡDoRve0l9AL
問題：46Please respect copyright.ＰＥＮＡＮＡW1Zl5AwdjR
> 由 2 開始，多一、再多一、再多一，最後是幾多？46Please respect copyright.ＰＥＮＡＮＡF0dD9gibix
步驟一：由 2 開始46Please respect copyright.ＰＥＮＡＮＡonTI8WHGlb
> 246Please respect copyright.ＰＥＮＡＮＡoYyPzhC1se
步驟二：第一次多一46Please respect copyright.ＰＥＮＡＮＡwxk1yiDM5d
> 2 → 346Please respect copyright.ＰＥＮＡＮＡZV0gaUcBfp
步驟三：第二次多一46Please respect copyright.ＰＥＮＡＮＡSEPdORwCJZ
> 3 → 446Please respect copyright.ＰＥＮＡＮＡpiTHxighZA
步驟四：第三次多一46Please respect copyright.ＰＥＮＡＮＡo4WjvGofH0
> 4 → 546Please respect copyright.ＰＥＮＡＮＡwxRFJF6CA9
所以最後是：46Please respect copyright.ＰＥＮＡＮＡbag6vhRJSN
> 5
你可以見到：46Please respect copyright.ＰＥＮＡＮＡylX13vrgvw
> 多一做三次，就是向右行三格。46Please respect copyright.ＰＥＮＡＮＡUiGLPYtABL
將來我們會將這件事寫成：46Please respect copyright.ＰＥＮＡＮＡHkmrmu2xrB
> 2 + 3 = 546Please respect copyright.ＰＥＮＡＮＡbeFcMQKU3R
九：連續少一46Please respect copyright.ＰＥＮＡＮＡTM9gLlvf4H
問題：46Please respect copyright.ＰＥＮＡＮＡ8bF13lTH0t
> 由 6 開始，少一、再少一，最後是幾多？46Please respect copyright.ＰＥＮＡＮＡhG6BLZgD56
步驟 1：由 6 開始46Please respect copyright.ＰＥＮＡＮＡYL9VAPf9Nn
> 646Please respect copyright.ＰＥＮＡＮＡvEhcyNGQU8
步驟 2：第一次少一46Please respect copyright.ＰＥＮＡＮＡxcAtFfoUDB
> 6 → 546Please respect copyright.ＰＥＮＡＮＡOcANDinNcc
步驟 3：第二次少一46Please respect copyright.ＰＥＮＡＮＡyk6rgJfmgn
> 5 → 446Please respect copyright.ＰＥＮＡＮＡHU4ylvokTd
所以最後是：46Please respect copyright.ＰＥＮＡＮＡOIJZOEjns1
> 446Please respect copyright.ＰＥＮＡＮＡdy9FwoeutN
將來我們會寫成：46Please respect copyright.ＰＥＮＡＮＡQQVwckAnKC
> 6 - 2 = 446Please respect copyright.ＰＥＮＡＮＡQwH4NlefYg
十：多一、少一和「相鄰數」46Please respect copyright.ＰＥＮＡＮＡCogYuaiKHh
兩個相鄰的整數，相差一定是 1。
例如：46Please respect copyright.ＰＥＮＡＮＡJ8OU5q9szA
> 4 和 5 相鄰46Please respect copyright.ＰＥＮＡＮＡjpqQI8KkqU
> 5 比 4 多一46Please respect copyright.ＰＥＮＡＮＡETPLuj7Qrh
> 4 比 5 少一46Please respect copyright.ＰＥＮＡＮＡuaEHoz3vtY
又例如：46Please respect copyright.ＰＥＮＡＮＡASr6cRa6Ku
> 8 和 9 相鄰46Please respect copyright.ＰＥＮＡＮＡyL2mALasAw
> 9 比 8 多一46Please respect copyright.ＰＥＮＡＮＡuvUxfvVZMA
> 8 比 9 少一46Please respect copyright.ＰＥＮＡＮＡN07vEBjcba
所以，如果有人問：46Please respect copyright.ＰＥＮＡＮＡKeSZYD6ZZv
> 哪兩個數是相鄰？46Please respect copyright.ＰＥＮＡＮＡ04TNZrE3b4
你可以看它們是不是只相差 1。
例如：46Please respect copyright.ＰＥＮＡＮＡZxLQmnJ5m4
> 6 和 7：相鄰46Please respect copyright.ＰＥＮＡＮＡoP55Jqxcq4
> 6 和 8：不相鄰，因為中間還有 7
十一：搵缺失的數46Please respect copyright.ＰＥＮＡＮＡ7J9CGf1CLO
數線其中一段是：46Please respect copyright.ＰＥＮＡＮＡ6eqlFB98rF
> 3 —— ? —— 546Please respect copyright.ＰＥＮＡＮＡWevoQqnbOf
問題：46Please respect copyright.ＰＥＮＡＮＡpzvmcLx41R
> ? 應該是幾多？46Please respect copyright.ＰＥＮＡＮＡoyLWAAfwSJ
步驟 1：由 3 向右一格46Please respect copyright.ＰＥＮＡＮＡPJvF9Gv2X0
3 後面下一個數是：46Please respect copyright.ＰＥＮＡＮＡf4cU3hva19
> 446Please respect copyright.ＰＥＮＡＮＡ7XPvm0npfC
步驟 2：由 5 向左一格46Please respect copyright.ＰＥＮＡＮＡui6MfO3B2W
5 前面上一個數都是：46Please respect copyright.ＰＥＮＡＮＡbbXr3SCcLG
> 446Please respect copyright.ＰＥＮＡＮＡwPhGZZco9C
所以：46Please respect copyright.ＰＥＮＡＮＡONbJGUIplh
> ? = 446Please respect copyright.ＰＥＮＡＮＡTOeUzXMSrD
完整數線為：46Please respect copyright.ＰＥＮＡＮＡUKUHnYba22
> 3 —— 4 —— 546Please respect copyright.ＰＥＮＡＮＡGzAKCmlzoV
十二：為何 9 多一是 10？
有時由 9 去 10 會覺得特別，因為寫法由一個符號變成兩個符號。
但概念上，它和其他「多一」一樣：46Please respect copyright.ＰＥＮＡＮＡYJG2sZFgrg
> 7 多一是 846Please respect copyright.ＰＥＮＡＮＡN0w8HYE1GN
> 8 多一是 946Please respect copyright.ＰＥＮＡＮＡ2CowFn0Z1Y
> 9 多一是 1046Please respect copyright.ＰＥＮＡＮＡ7qK30GxpDT
意思都是：46Please respect copyright.ＰＥＮＡＮＡSvC4Vkl8B9
> 數線上向右行一格。46Please respect copyright.ＰＥＮＡＮＡE5Sl6im7Pn
10 只是寫法變了，數量仍然是「9 再多一」。
例如：46Please respect copyright.ＰＥＮＡＮＡyLTxBEDgoi
> ⭐⭐⭐⭐⭐⭐⭐⭐⭐46Please respect copyright.ＰＥＮＡＮＡDwwhMIG5yh
這裏是 9 粒星。
再加一粒：46Please respect copyright.ＰＥＮＡＮＡUsU1bD86Kw
> ⭐⭐⭐⭐⭐⭐⭐⭐⭐⭐46Please respect copyright.ＰＥＮＡＮＡcwAzdUNJxe
就是 10 粒星。46Please respect copyright.ＰＥＮＡＮＡXKCJmjcA6E
所以：46Please respect copyright.ＰＥＮＡＮＡTa54Za2OFy
> 雖然寫法變複雜，但「多一」的意思沒有變。46Please respect copyright.ＰＥＮＡＮＡsW2C284hsu
十三：由 4 出發46Please respect copyright.ＰＥＮＡＮＡYdfldOSbDJ
問題：46Please respect copyright.ＰＥＮＡＮＡo62RhqlWxY
1. 4 多一是幾多？46Please respect copyright.ＰＥＮＡＮＡx2i1QVdJ8o
2. 4 少一是幾多？46Please respect copyright.ＰＥＮＡＮＡY8284rkzeA
3. 4 多一之後再少一是幾多？46Please respect copyright.ＰＥＮＡＮＡ3DDgK27NAb
4. 4 少一之後再少一是幾多？46Please respect copyright.ＰＥＮＡＮＡjITrLG7paw
第 1 問46Please respect copyright.ＰＥＮＡＮＡwCNnehVWVv
> 4 → 546Please respect copyright.ＰＥＮＡＮＡ38NOOmiZ32
所以：46Please respect copyright.ＰＥＮＡＮＡcpOoOXNXrg
> 4 多一是 546Please respect copyright.ＰＥＮＡＮＡs28JAgwl2b
//
第 2 問46Please respect copyright.ＰＥＮＡＮＡSiwBnXbTn9
> 4 → 3
所以：46Please respect copyright.ＰＥＮＡＮＡzKlxd8XPrO
> 4 少一是 346Please respect copyright.ＰＥＮＡＮＡyjmC4FFjAT
//
第 3 問46Please respect copyright.ＰＥＮＡＮＡ8GUC8r7tk4
4 多一：46Please respect copyright.ＰＥＮＡＮＡhTqFq22nJo
> 4 → 546Please respect copyright.ＰＥＮＡＮＡTXVWUcMgs7
再少一：46Please respect copyright.ＰＥＮＡＮＡLdKzvKlwRF
> 5 → 446Please respect copyright.ＰＥＮＡＮＡShxTznIhcc
所以最後是：46Please respect copyright.ＰＥＮＡＮＡasWMHBfe0n
> 446Please respect copyright.ＰＥＮＡＮＡCWO1oU5MpN
//
第 4 問46Please respect copyright.ＰＥＮＡＮＡV4MZ45eJDj
4 少一：46Please respect copyright.ＰＥＮＡＮＡjOzgDzmhFp
> 4 → 346Please respect copyright.ＰＥＮＡＮＡfl4EM6dbIr
再少一：46Please respect copyright.ＰＥＮＡＮＡUsaSn4A76Y
> 3 → 2
所以最後是：46Please respect copyright.ＰＥＮＡＮＡrSz9dLLqWA
> 246Please respect copyright.ＰＥＮＡＮＡJ7d2FH50bo
十四：今日小結46Please respect copyright.ＰＥＮＡＮＡjGvKUDMlhZ
今課你掌握了：
1. 多一即是數線上向右行一格。46Please respect copyright.ＰＥＮＡＮＡxqjdysGff1
2. 少一即是數線上向左行一格。46Please respect copyright.ＰＥＮＡＮＡlZ5Wbghk48
3. 一個數的後繼數，就是它多一之後的數。46Please respect copyright.ＰＥＮＡＮＡYF3QRmd7HO
4. 一個數的前一個數，就是它少一之後的數。46Please respect copyright.ＰＥＮＡＮＡ9rHaeOhjAx
5. 多一和少一是相反動作。46Please respect copyright.ＰＥＮＡＮＡ5lTb0FGzq4
6. 連續多一，可以理解成將來的加法：連續少一，可以理解成將來的減法。
數學之間不是散開的；每個數都和前後的數連住，而「一」就是最基本的步伐。
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and then Add to home screen.