Simple equations (I)
An equation is a statement with an unknown where both sides are equal; using a balance to show the steps of solving (do the same thing to both sides); solving the eight kinds of simple equation such as x + b = c, ax = b, ax + b = c and x/a − b = c (a, b and c whole numbers); checking by putting the answer back in; and writing an equation straight from the story to solve word problems.
Key words
| Chinese | English |
|---|---|
| 方程 | equation |
| 解方程 | solve an equation |
| 方程的解 | solution of an equation |
| 驗算 | check |
The 8 short lessons and the chapter test
Lessons are in Chinese for now.
- 認識方程
- 方程的解
- 天平和方程
- 一步方程
- 兩步方程
- 列方程
- 列方程解應用題
- 綜合練習
- 章節測驗 (chapter test)
Sample questions (in Chinese)
Question 1下面哪一個是方程？
- 9 + 14 = 23
- 3y − 8
- 3y − 8 = 79
- y + y + 14
Answer and explanation
答案：C．3y − 8 = 79
為甚麼？方程是含有未知數的等式：要有「=」，也要有用字母表示的未知數。3y − 8 = 79 兩樣都有，所以是方程。
Question 2這句話對還是錯？
m = 9 是方程 2m + 6 = 24 的解。
- 對
- 錯
Answer and explanation
答案：A．對
為甚麼？把 m = 9 代入：左邊 = 2 × 9 + 6 = 24，等於右邊 24，所以 m = 9 是方程的解。
Question 3解方程：9y = 243
y =
Answer and explanation
答案：y = 27
為甚麼？方程兩邊同時加、減、乘或除以同一個數（除數不是 0），兩邊仍然相等。兩邊同時除以 9：9y ÷ 9 = 243 ÷ 9，所以 y = 27。驗算：把 y = 27 代入，左邊 = 9 × 27 = 243 = 右邊。
Question 4解方程：m8 − 2 = 1
m =
Answer and explanation
答案：m = 24
為甚麼？方程兩邊同時加、減、乘或除以同一個數（除數不是 0），兩邊仍然相等。兩邊同時加上 2：m8 = 3；兩邊同時乘以 8：m = 3 × 8，所以 m = 24。驗算：把 m = 24 代入，左邊 = 24 ÷ 8 − 2 = 1 = 右邊。
Based on learning unit 5A2 of the Education Bureau’s Primary Mathematics Curriculum (2017).