數線 國 小

數線

數線三要素：

1. 正向：直線右方畫上箭頭，表示正向。
2. 原點：數線上的基準點，其所代表的數為 $0$。
3. 單位長：取適當長度當作 $1$ 個單位，稱為單位長。

坐標

坐標：數線上每一個點都代表一個數，這個數稱為這個點的坐標。

$A$ 點在原點右方 $3$ 個單位，即 $A$ 點的坐標為 $3$，記作 $A(3)$。

$B$ 點在原點左方 $2$ 個單位，即 $B$ 點的坐標為 $-2$ ，記作 $B(-2)$。

小數與數線

Junyi Academy is derived originally from Khan Academy, and derived from Chengzhi Foundation.

More information about Chengzhi Foundation, you can find under: http://kistschool.org/.

More information about Khan Academy, you can find under: https://www.khanacademy.org/.

Junyi Academy is derived originally from Khan Academy, and derived from Chengzhi Foundation.

More information about Chengzhi Foundation, you can find under: http://kistschool.org/.

More information about Khan Academy, you can find under: https://www.khanacademy.org/.