一、加法不一定逐步數
上一課我們學了：12Please respect copyright.ＰＥＮＡＮＡcUKXKEcT2X
> 8 + 312Please respect copyright.ＰＥＮＡＮＡBP5gQOys2O
可以由 8 開始接住數：12Please respect copyright.ＰＥＮＡＮＡOsxHkuLept
> 8 → 9 → 10 → 11
所以：12Please respect copyright.ＰＥＮＡＮＡYnyjPUXh9Q
> 8 + 3 = 1112Please respect copyright.ＰＥＮＡＮＡHoF6GZgZEd
這個方法很有用。
但如果數字再大一些，每次都一步一步數，仍然會慢。
例如：12Please respect copyright.ＰＥＮＡＮＡzGQ1w1mZhe
> 8 + 712Please respect copyright.ＰＥＮＡＮＡs0BjjUTWO3
你可以由 8 開始數 7 步，但有沒有更聰明的方法？
今課我們會開始找加法規律，尤其是一個很重要的技巧：12Please respect copyright.ＰＥＮＡＮＡcsyvIabNKq
> 湊十 | Making Ten12Please respect copyright.ＰＥＮＡＮＡgL9s23LEt8
二、為何 10 很重要？
我們日常用的數字系統很依賴 10。
例如：12Please respect copyright.ＰＥＮＡＮＡjJ3Wzy9sWv
> 10、20 、30、100、100012Please respect copyright.ＰＥＮＡＮＡHlKAbie5Pb
好多大數都是圍繞 10 而建立。
所以如果你熟悉哪些數可以湊成 10，之後做加法會快好多。
例如：12Please respect copyright.ＰＥＮＡＮＡWocoytx7Rw
> 8 + 2 = 1012Please respect copyright.ＰＥＮＡＮＡCN4lFlm0Qx
> 7 + 3 = 1012Please respect copyright.ＰＥＮＡＮＡJz4eeZBez0
> 6 + 4 = 1012Please respect copyright.ＰＥＮＡＮＡKioH15wtcM
> 5 + 5 = 1012Please respect copyright.ＰＥＮＡＮＡYyE7Cvi9gX
這些叫：12Please respect copyright.ＰＥＮＡＮＡTFwTWr26xX
> 湊十組合 | Number bonds to 1012Please respect copyright.ＰＥＮＡＮＡ3gBKaWEttL
可以理解成：12Please respect copyright.ＰＥＮＡＮＡwrkHHIGmUx
> 兩個部分合起來，剛好成為 10。12Please respect copyright.ＰＥＮＡＮＡz1bTmaAs5L
三、先記住 10 的組合
以下是最基本的湊十組合：12Please respect copyright.ＰＥＮＡＮＡsPHk2cIA7h
> 0 + 10 = 1012Please respect copyright.ＰＥＮＡＮＡ5FiNxgUfWN
> 1 + 9 = 1012Please respect copyright.ＰＥＮＡＮＡxsNYYi1kxM
> 2 + 8 = 1012Please respect copyright.ＰＥＮＡＮＡ1BNUlWKKTo
> 3 + 7 = 1012Please respect copyright.ＰＥＮＡＮＡNScFPBYSYn
> 4 + 6 =1012Please respect copyright.ＰＥＮＡＮＡbatlTBRNwt
> 5 + 5 = 1012Please respect copyright.ＰＥＮＡＮＡY02DaxDgih
> 6 + 4 = 1012Please respect copyright.ＰＥＮＡＮＡdgYRwBAH7L
> 7 + 3 = 1012Please respect copyright.ＰＥＮＡＮＡBy9VmjH4GD
> 8 + 2 = 1012Please respect copyright.ＰＥＮＡＮＡrDCDtPGqdB
> 9 + 1 = 1012Please respect copyright.ＰＥＮＡＮＡ7lnQR4oWGK
> 10 + 0 = 1012Please respect copyright.ＰＥＮＡＮＡOWLewGqS97
你會見到：12Please respect copyright.ＰＥＮＡＮＡU4N2X3VCxJ
> 1 配 912Please respect copyright.ＰＥＮＡＮＡY7SyZhcafB
> 2 配 812Please respect copyright.ＰＥＮＡＮＡlLK8RLEVQj
> 3 配 712Please respect copyright.ＰＥＮＡＮＡiiCXzz7DDo
> 4 配 612Please respect copyright.ＰＥＮＡＮＡhr8Up7xvDw
> 5 配 512Please respect copyright.ＰＥＮＡＮＡuTjD2IHa01
如果交換次序，答案仍然一樣。
例如：12Please respect copyright.ＰＥＮＡＮＡvGyEolnweI
> 3 + 7 = 1012Please respect copyright.ＰＥＮＡＮＡli34euGbsf
> 7 + 3 = 1012Please respect copyright.ＰＥＮＡＮＡJMcQLibozR
四、簡單例子：直接湊十
例子 1：8 + 212Please respect copyright.ＰＥＮＡＮＡOJNUxAMIcC
8 距離 10 差幾多？12Please respect copyright.ＰＥＮＡＮＡiynD4pZPET
> 8 → 9：第 1 步12Please respect copyright.ＰＥＮＡＮＡIdzCOzy1xp
> 9 → 10：第 2 步12Please respect copyright.ＰＥＮＡＮＡ3OSxW5hdRv
所以 8 差 2 到 10。
因此：12Please respect copyright.ＰＥＮＡＮＡyKALEfa6iH
> 8 + 2 = 1012Please respect copyright.ＰＥＮＡＮＡkfOroaFBVO
//
例子 2：6 + 4
6 距離 10 差幾多？12Please respect copyright.ＰＥＮＡＮＡsLomSS1SSW
> 6 → 7：第 1 步12Please respect copyright.ＰＥＮＡＮＡ0Vj2a8zVUB
> 7 → 8：第 2 步12Please respect copyright.ＰＥＮＡＮＡgdiQWpQ2af
> 8 → 9：第 3 步12Please respect copyright.ＰＥＮＡＮＡmAUs2FhfEK
> 9 → 10：第 4 步12Please respect copyright.ＰＥＮＡＮＡoO3pWkrnlW
所以 6 差 4 到 10。
因此：12Please respect copyright.ＰＥＮＡＮＡWMb6G6K7ak
> 6 + 4 = 1012Please respect copyright.ＰＥＮＡＮＡxDJ3cyQmJ6
//
例子 3：9 + 1
9 只差 1 就到 10：12Please respect copyright.ＰＥＮＡＮＡ739zGXblon
> 9 → 1012Please respect copyright.ＰＥＮＡＮＡsrZWJPn3Ol
所以：12Please respect copyright.ＰＥＮＡＮＡ9EzsVpJpZN
> 9 + 1 = 1012Please respect copyright.ＰＥＮＡＮＡKZi7rr8CCW
五、湊十如何幫助加法？
如果題目是：12Please respect copyright.ＰＥＮＡＮＡ0VxO4AeYMT
> 8 + 512Please respect copyright.ＰＥＮＡＮＡ7bBTUgyRb5
你可以逐步數：12Please respect copyright.ＰＥＮＡＮＡDs7CqeqIaX
> 8 → 9 → 10 → 11 → 12 → 1312Please respect copyright.ＰＥＮＡＮＡNVcKpdTJB2
答案是 13。
但湊十可以令思考更清楚。
步驟 1：先問 8 差幾多到 1012Please respect copyright.ＰＥＮＡＮＡ3cr05MWO5a
> 8 差 2 到 10
所以將 5 拆開成：12Please respect copyright.ＰＥＮＡＮＡodEDAj0AKH
> 2 + 312Please respect copyright.ＰＥＮＡＮＡnWvbJMHYBT
因為：12Please respect copyright.ＰＥＮＡＮＡyIJVlstH2H
> 5 = 2 + 312Please respect copyright.ＰＥＮＡＮＡeTId5Nulm4
步驟 2：先用 2 湊成 1012Please respect copyright.ＰＥＮＡＮＡAQaDxGwS2y
> 8 + 2 = 1012Please respect copyright.ＰＥＮＡＮＡch8djtUBKM
步驟 3：再加剩低的 312Please respect copyright.ＰＥＮＡＮＡTEKgd9ER2D
> 10 + 3 = 1312Please respect copyright.ＰＥＮＡＮＡBdKG08tWT1
所以：12Please respect copyright.ＰＥＮＡＮＡKL3M2MTJdz
> 8 + 5 = 1312Please respect copyright.ＰＥＮＡＮＡOZKiSlF4l3
完整想法：12Please respect copyright.ＰＥＮＡＮＡRb2FOUkgoI
> 8 + 512Please respect copyright.ＰＥＮＡＮＡvqPHcrU3U4
> = 8 + 2 + 312Please respect copyright.ＰＥＮＡＮＡC3odry893e
> = 10 + 312Please respect copyright.ＰＥＮＡＮＡhuiZSMoAnP
> = 1312Please respect copyright.ＰＥＮＡＮＡhQ0l0smZBF
湊十的核心是：12Please respect copyright.ＰＥＮＡＮＡJBf8uPZw9r
> 先去到 10，再接住加剩低那部分。
六、數字拆分：將一個數分成兩部分
要湊十，通常要將一個數拆開。12Please respect copyright.ＰＥＮＡＮＡEgQbslmUV7
例如：12Please respect copyright.ＰＥＮＡＮＡrgLN3i1qWu
> 5 可以拆成 2 + 312Please respect copyright.ＰＥＮＡＮＡ8DFjOocVMl
> 6 可以拆成 1 + 512Please respect copyright.ＰＥＮＡＮＡP7VIZ4HVnr
> 7 可以拆成 2 + 512Please respect copyright.ＰＥＮＡＮＡChiQqNY4xv
> 4 可以拆成 1 + 312Please respect copyright.ＰＥＮＡＮＡLUCGHvnmQY
拆分不代要改變數量，只是將同一個數分成兩部分。
例如 5 粒糖果：12Please respect copyright.ＰＥＮＡＮＡgBcdsJAsc3
> 🍬 🍬 | 🍬 🍬 🍬12Please respect copyright.ＰＥＮＡＮＡz2AscIfDIN
左邊 2 粒，右邊 3 粒。
所以：12Please respect copyright.ＰＥＮＡＮＡEv7aonBX6j
> 5 = 2 + 312Please respect copyright.ＰＥＮＡＮＡwvC6JygYpF
但總數仍然是 5。
七：簡單例子：9 + 4
問題：12Please respect copyright.ＰＥＮＡＮＡADYJ5j7kaw
> 9 + 4= ?12Please respect copyright.ＰＥＮＡＮＡIefj6nLMpn
步驟 1：9 差幾多到 10？12Please respect copyright.ＰＥＮＡＮＡtbMkYlB39u
> 9 差 1 到 10
步驟 2：將 4 拆成 1 + 312Please respect copyright.ＰＥＮＡＮＡrl08z0N5bZ
> 4 = 1 + 3
步驟 3：先湊十12Please respect copyright.ＰＥＮＡＮＡTtOQmwTf49
> 9 + 1 = 1012Please respect copyright.ＰＥＮＡＮＡnLNiG8axK0
步驟 4：再加剩低的 312Please respect copyright.ＰＥＮＡＮＡtYHG27wUYc
> 10 + 3 = 1312Please respect copyright.ＰＥＮＡＮＡIRbAaf9En3
所以：12Please respect copyright.ＰＥＮＡＮＡs4u88QbTvv
> 9 + 4 = 1312Please respect copyright.ＰＥＮＡＮＡ7tBryAwV9z
完整：12Please respect copyright.ＰＥＮＡＮＡdm1EzMX9WH
> 9 + 412Please respect copyright.ＰＥＮＡＮＡPFOa0GyuLg
> = 9 + 1 + 312Please respect copyright.ＰＥＮＡＮＡbrQAM5QPyK
> = 10 + 312Please respect copyright.ＰＥＮＡＮＡeKus9b3B07
> = 1312Please respect copyright.ＰＥＮＡＮＡa4hafl07X9
八、7 + 5
問題：12Please respect copyright.ＰＥＮＡＮＡlauIQsbZAn
> 7 + 5 = ?12Please respect copyright.ＰＥＮＡＮＡHk838QGOjI
步驟 1：7 差幾多到 10？12Please respect copyright.ＰＥＮＡＮＡ3EWwAaXLnf
由 7 到 10：12Please respect copyright.ＰＥＮＡＮＡ798TS5Xb0y
> 7 → 8：第 1 步12Please respect copyright.ＰＥＮＡＮＡfDAiBPCfYF
> 8 → 9：第 2 步12Please respect copyright.ＰＥＮＡＮＡ2FYdYaZNU0
> 9 → 10：第 3 步12Please respect copyright.ＰＥＮＡＮＡKdmlrYTKzz
所以：12Please respect copyright.ＰＥＮＡＮＡOObis2wRhZ
> 7 差 3 到 1012Please respect copyright.ＰＥＮＡＮＡFUNdcUPmOF
步驟 2：將 5 拆成 3 + 212Please respect copyright.ＰＥＮＡＮＡ19yFr85UGE
> 5 = 3 + 212Please respect copyright.ＰＥＮＡＮＡ6wt9rIvGzE
步驟 3：先湊十12Please respect copyright.ＰＥＮＡＮＡLIPf57ue3B
> 7 + 3 = 1012Please respect copyright.ＰＥＮＡＮＡZIhSyfZc5G
步驟 4：再加剩低的 212Please respect copyright.ＰＥＮＡＮＡWbldxLlbOd
> 10 + 2 = 1212Please respect copyright.ＰＥＮＡＮＡSjJ0WF46cE
所以：12Please respect copyright.ＰＥＮＡＮＡH6KJpHJnCY
> 7 + 5 =1212Please respect copyright.ＰＥＮＡＮＡoRr0CKaIWe
九、6 + 8
問題：12Please respect copyright.ＰＥＮＡＮＡuIu3qbmaPz
> 6 + 8 = ?12Please respect copyright.ＰＥＮＡＮＡYRhVQuZlNj
這條題目有兩個方向。
方向 A：由 6 湊十12Please respect copyright.ＰＥＮＡＮＡCr9oUXtz4S
6 差 4 到 10。12Please respect copyright.ＰＥＮＡＮＡG7sQcfMLPm
所以將 8 拆成：12Please respect copyright.ＰＥＮＡＮＡS4EdnLsDoY
> 4 + 4
然後：12Please respect copyright.ＰＥＮＡＮＡ46GHq8TPa4
> 6 + 812Please respect copyright.ＰＥＮＡＮＡ2no7RcXwuX
> = 6 + 4 + 412Please respect copyright.ＰＥＮＡＮＡ3qH6eWHtPB
> = 10 + 412Please respect copyright.ＰＥＮＡＮＡknyaoSCrgQ
> = 1412Please respect copyright.ＰＥＮＡＮＡlAXAnP4Aew
答案：12Please respect copyright.ＰＥＮＡＮＡ9b5GZno9Ad
> 1412Please respect copyright.ＰＥＮＡＮＡNZWcoyVYt5
//
方法 B：由 8 湊十12Please respect copyright.ＰＥＮＡＮＡkbOjtCLJqP
8 差 2 到 10。
所以將 6 拆成：12Please respect copyright.ＰＥＮＡＮＡ8O7MkNu6i7
> 2 + 412Please respect copyright.ＰＥＮＡＮＡgiY6D7kCSr
然後：12Please respect copyright.ＰＥＮＡＮＡBWoXDnhNkK
> 8 + 612Please respect copyright.ＰＥＮＡＮＡaCtcHkLgCN
> = 8 + 2 + 412Please respect copyright.ＰＥＮＡＮＡIGlAsIeqrb
> = 10 + 412Please respect copyright.ＰＥＮＡＮＡCTLgFgEbUY
> = 14
答案一樣12Please respect copyright.ＰＥＮＡＮＡJUIOxaMJdZ
> 1412Please respect copyright.ＰＥＮＡＮＡJXKeVxGL6w
//
哪個方法更自然？12Please respect copyright.ＰＥＮＡＮＡZJE42RmbMH
通常由較接近 10 的數開始會容易一些。12Please respect copyright.ＰＥＮＡＮＡaDhVmu7vNn
8 比 6 更接近 10，所以：12Please respect copyright.ＰＥＮＡＮＡKgzO3fzEhZ
> 8 + 612Please respect copyright.ＰＥＮＡＮＡRxOhTy7oUH
會比較容易思考：12Please respect copyright.ＰＥＮＡＮＡZF26x53yhF
> 8 差 2，到 10，再剩 4。12Please respect copyright.ＰＥＮＡＮＡMCsKKmyFoV
所以：12Please respect copyright.ＰＥＮＡＮＡof9eIsw8gj
> 8 + 6 = 1412Please respect copyright.ＰＥＮＡＮＡPIH7K8EU1P
十、加法規律：雙倍
有一類加法特別容易記：12Please respect copyright.ＰＥＮＡＮＡLTt2k8gTrg
> 1 + 1 = 212Please respect copyright.ＰＥＮＡＮＡOK07EqA9O5
> 2 + 2 = 412Please respect copyright.ＰＥＮＡＮＡnsDjlnax0q
> 3 + 3 = 612Please respect copyright.ＰＥＮＡＮＡkhYFtbdMLZ
> 4 + 4 = 812Please respect copyright.ＰＥＮＡＮＡenzB9vrFzV
> 5 + 5 = 1012Please respect copyright.ＰＥＮＡＮＡWdV2yythgH
> 6 + 6 = 1212Please respect copyright.ＰＥＮＡＮＡ4iXksEJ9n5
> 7 + 7 = 1412Please respect copyright.ＰＥＮＡＮＡzwNYMfOz1J
> 8 + 8 = 1612Please respect copyright.ＰＥＮＡＮＡBLntp6Vk8d
> 9 + 9 = 1812Please respect copyright.ＰＥＮＡＮＡSW8v7SsrhL
> 10 + 10 = 2012Please respect copyright.ＰＥＮＡＮＡtJOKzvnBRJ
這些叫：12Please respect copyright.ＰＥＮＡＮＡX21sL9bBPw
> 雙倍數 | Doubles12Please respect copyright.ＰＥＮＡＮＡ5E1dz9l0Pp
意思是：12Please respect copyright.ＰＥＮＡＮＡuPRgRG1FKi
> 同一個數加自己。12Please respect copyright.ＰＥＮＡＮＡn2A5QLJV4M
例如：12Please respect copyright.ＰＥＮＡＮＡqjEpUXLxF7
> 6 + 6 = 12
雙倍數加法很重要，因為好多加法都可以靠近它。
十一、接近雙倍數：Near Doubles
例如：12Please respect copyright.ＰＥＮＡＮＡCnkGQ9ISVx
> 6 + 712Please respect copyright.ＰＥＮＡＮＡ3JMrDQzy5k
7 比 6 多 1。
你可以先想：12Please respect copyright.ＰＥＮＡＮＡ8qBvYBfUDZ
> 6 + 6 = 1212Please respect copyright.ＰＥＮＡＮＡPKAjvs1KQW
再加 1：12Please respect copyright.ＰＥＮＡＮＡ2lvC1nTgE5
> 12 + 1 = 13
所以：12Please respect copyright.ＰＥＮＡＮＡea2Wbd6Mrv
> 6 + 7 = 1312Please respect copyright.ＰＥＮＡＮＡbYyLeh6Ke3
//
又例如：12Please respect copyright.ＰＥＮＡＮＡ8Sqrj8EvIU
> 8 + 912Please respect copyright.ＰＥＮＡＮＡN1B8UyuXaL
先想：12Please respect copyright.ＰＥＮＡＮＡu9FhE3FSR6
> 8 + 8 = 1612Please respect copyright.ＰＥＮＡＮＡVRHAhco78L
再多 1：12Please respect copyright.ＰＥＮＡＮＡjXCWVJwS9C
> 16 + 1 = 1712Please respect copyright.ＰＥＮＡＮＡlLCuDxCkIZ
所以：12Please respect copyright.ＰＥＮＡＮＡcmRrljnxng
> 8 + 9 = 1712Please respect copyright.ＰＥＮＡＮＡoYHLM7m2Fc
這個叫：12Please respect copyright.ＰＥＮＡＮＡbE3URvXdTo
> 接近雙倍數 | Near Doubles12Please respect copyright.ＰＥＮＡＮＡuQruM7hmQk
即是：12Please respect copyright.ＰＥＮＡＮＡYgayRmvYKa
> 兩個數差 1，可以先用雙數，再調整 1。12Please respect copyright.ＰＥＮＡＮＡX9n1aHuPjm
十二、7 + 8
問題：12Please respect copyright.ＰＥＮＡＮＡ2Z6JGgonuC
> 7 + 8 = ?12Please respect copyright.ＰＥＮＡＮＡR3ydbN4NTO
可以用湊十，也可以用接近雙倍數。
方法 A：12Please respect copyright.ＰＥＮＡＮＡEVNmdZS3sa
8 差 2 到 10：12Please respect copyright.ＰＥＮＡＮＡqjScRswNYg
將 7 拆成：12Please respect copyright.ＰＥＮＡＮＡ2BzXLv9fpg
> 2 + 512Please respect copyright.ＰＥＮＡＮＡkGoUMGFkKC
所以：12Please respect copyright.ＰＥＮＡＮＡjZRdpzqAtE
> 8 + 712Please respect copyright.ＰＥＮＡＮＡGXaHFp6mIc
> = 8 + 2 + 512Please respect copyright.ＰＥＮＡＮＡNswrUuQivC
> = 10 + 512Please respect copyright.ＰＥＮＡＮＡO1VrNfDbqw
> = 1512Please respect copyright.ＰＥＮＡＮＡIkXOjAbSp3
//
方法 B：接近雙倍數12Please respect copyright.ＰＥＮＡＮＡb1ifRFWfVr
先想：12Please respect copyright.ＰＥＮＡＮＡFw8WNNjtq7
> 7 + 7 = 1412Please respect copyright.ＰＥＮＡＮＡL2pjXWVhU8
而 8 比 7 多 1。
所以：12Please respect copyright.ＰＥＮＡＮＡzn3wkFCufx
> 7 + 8 = 1512Please respect copyright.ＰＥＮＡＮＡr4fEmYuvxN
兩個方法都對。
重點是：12Please respect copyright.ＰＥＮＡＮＡ9XgC48bSne
> 數學可以有多一條合理解題路線。12Please respect copyright.ＰＥＮＡＮＡvGjNLelWLM
十三、加 9 的規律
加 9 可以用很有效率地湊 10。12Please respect copyright.ＰＥＮＡＮＡJihwwehN6K
例如：12Please respect copyright.ＰＥＮＡＮＡQUw4BOsrTc
> 6 + 912Please respect copyright.ＰＥＮＡＮＡGUaNGIUrmz
9 差 1 到 10。
可以由 6 借 1 給 9：12Please respect copyright.ＰＥＮＡＮＡ6LFP34Khef
> 9 + 1 = 1012Please respect copyright.ＰＥＮＡＮＡWi5OBNGf6z
6 借走 1 之後剩：12Please respect copyright.ＰＥＮＡＮＡnZDLSMH1jy
> 512Please respect copyright.ＰＥＮＡＮＡBKNNGLmBWU
所以：12Please respect copyright.ＰＥＮＡＮＡp7F2Gze9wS
> 6 + 912Please respect copyright.ＰＥＮＡＮＡ9LOTkHTQRA
> = 5 + 1012Please respect copyright.ＰＥＮＡＮＡxs0MhgXjwS
> = 1512Please respect copyright.ＰＥＮＡＮＡKWfcOPn5SM
另一個寫法：12Please respect copyright.ＰＥＮＡＮＡTVsd9hosQX
> 9 + 612Please respect copyright.ＰＥＮＡＮＡX8K2W0i7Pl
> = 9 + 1 + 512Please respect copyright.ＰＥＮＡＮＡadp5e0k6hp
> = 10 + 512Please respect copyright.ＰＥＮＡＮＡ7yIrGPCQXB
> = 1512Please respect copyright.ＰＥＮＡＮＡzbaQG0cPMV
加 9 的直覺可以是：12Please respect copyright.ＰＥＮＡＮＡoh51ABxUlU
> 加 10 再少 112Please respect copyright.ＰＥＮＡＮＡTwhOZg2alr
例如：12Please respect copyright.ＰＥＮＡＮＡlAy9uSnpdU
> 6 + 10 = 1612Please respect copyright.ＰＥＮＡＮＡXN5MfPICTS
> 6 + 9 = 1512Please respect copyright.ＰＥＮＡＮＡrneIzNIJYY
因為 9 比 10 少 1。
十四、加法規律不是魔法
今課有很多技巧：12Please respect copyright.ＰＥＮＡＮＡgAowPGJUAi
> 湊十、雙倍數、接近雙倍數、加 912Please respect copyright.ＰＥＮＡＮＡlXRrfO01Uq
但所技巧都要回到同一個基礎：12Please respect copyright.ＰＥＮＡＮＡ3WJYNjQATO
> 數量沒有改變，只是拆分與重組。12Please respect copyright.ＰＥＮＡＮＡWq4O1TM2BR
例如：12Please respect copyright.ＰＥＮＡＮＡEOI92we9qm
> 8 + 512Please respect copyright.ＰＥＮＡＮＡHE8XGp11mX
改成：12Please respect copyright.ＰＥＮＡＮＡxdOYee5f75
> 8 + 2 + 312Please respect copyright.ＰＥＮＡＮＡYkmLQOaY6T
這裏沒有偷偷地改答案，因為：12Please respect copyright.ＰＥＮＡＮＡbZleLBAsTx
> 5 = 2 + 312Please respect copyright.ＰＥＮＡＮＡijj6uJKHWb
數學技巧可靠，因為每一步都保持數量相等。
十五、綜合例子：選擇一個好方法
題目 1：9 + 712Please respect copyright.ＰＥＮＡＮＡmNuyBPVbXN
9 接近 10，所以用湊十。
9 差 1 到 10。12Please respect copyright.ＰＥＮＡＮＡaCxFLSocHe
將 7 拆成：12Please respect copyright.ＰＥＮＡＮＡ8CC4FyyGOK
> 1 + 612Please respect copyright.ＰＥＮＡＮＡaFAwKw3JaD
所以：12Please respect copyright.ＰＥＮＡＮＡFFr0HhkMBT
> 9 + 712Please respect copyright.ＰＥＮＡＮＡt2uW1pnBQQ
> = 9 + 1 + 612Please respect copyright.ＰＥＮＡＮＡohIRt6yutr
> = 10 + 612Please respect copyright.ＰＥＮＡＮＡBUm7q91CIm
> = 1612Please respect copyright.ＰＥＮＡＮＡAu8bcYnKLY
答案：12Please respect copyright.ＰＥＮＡＮＡCjwzj5FIah
> 1612Please respect copyright.ＰＥＮＡＮＡ5fv186knmL
//
題目 2：6 + 612Please respect copyright.ＰＥＮＡＮＡ3PQAUYPxyn
兩個數一樣，用雙倍數：12Please respect copyright.ＰＥＮＡＮＡzi9m2lNYD1
> 6 + 6 = 1212Please respect copyright.ＰＥＮＡＮＡV1txWNdjTr
答案：12Please respect copyright.ＰＥＮＡＮＡf4sUS0Y0fL
> 1212Please respect copyright.ＰＥＮＡＮＡKV4QBuSWql
//
題目 3：6 + 712Please respect copyright.ＰＥＮＡＮＡC4gHojJrLY
兩個數差 1，用接近雙倍數12Please respect copyright.ＰＥＮＡＮＡaM8vj6y4Ir
> 6 + 6 = 1212Please respect copyright.ＰＥＮＡＮＡscDNLF34sz
> 再多 1 = 13
所以：12Please respect copyright.ＰＥＮＡＮＡ9mFwe2Nnh4
> 6 + 7 = 1312Please respect copyright.ＰＥＮＡＮＡB3mk98M9Yb
十六、今日小結
今課你掌握了：12Please respect copyright.ＰＥＮＡＮＡ7AW18qGPGf
1. 10 是重要標準，熟悉湊十可以加法更法。12Please respect copyright.ＰＥＮＡＮＡO0fBb4YhRL
2. 湊十組合包括：1 + 9、2 + 8、3 + 7、4 + 6、5 + 5。12Please respect copyright.ＰＥＮＡＮＡrDMnjDjt94
3. 做湊十時，可以將一個數拆成兩部分。12Please respect copyright.ＰＥＮＡＮＡrJbLpKfGxo
4. 例如 8 + 5 可以想成 8 + 2 + 3 = 10 + 3 = 13。12Please respect copyright.ＰＥＮＡＮＡ59IZp6CPwE
5. 雙倍數加法是同一個數加自己，例如 6 + 6 = 12。12Please respect copyright.ＰＥＮＡＮＡbsr5E1tKBS
6. 接近雙倍數可以先用雙倍數，再多一或少一。12Please respect copyright.ＰＥＮＡＮＡRDBbMcTJPI
7. 所有加法技巧都要保持原本數量不變。
湊十是將加法重新安排，先去到 10，再從 10 繼續前進。
ns216.73.216.75da2
and then Add to home screen.