Division (I)
A 2-digit or 3-digit number divided by a 1-digit number, with borrowing and remainders, in column form and why it works (68 ÷ 2 is 60 ÷ 2 plus 8 ÷ 2); dividing three numbers from left to right, so 24 ÷ 6 ÷ 2 = 2, not 24 ÷ 3; estimating quotients; and word problems.
Key words
| Chinese | English |
|---|---|
| 除法 | division |
| 被除數 | dividend |
| 除數 | divisor |
| 商 | quotient |
| 餘數 | remainder |
| 估算 | estimate |
The 8 short lessons and the chapter test
Lessons are in Chinese for now.
- 拆開來除
- 退位除法
- 三位數除以一位數
- 有餘數的除法
- 被除數、商和餘數
- 三個數相除
- 估算
- 應用題
- 章節測驗 (chapter test)
Sample questions (in Chinese)
Question 1把 408 拆成 360 和 48，再計算。
408 ÷ 6 = 360 ÷ 6 + 48 ÷ 6
= +
=
Answer and explanation
答案：408 ÷ 6 = 360 ÷ 6 + 48 ÷ 6
= 60 + 8
= 68
為甚麼？360 ÷ 6 = 60，48 ÷ 6 = 8，合起來是 68。所以 408 ÷ 6 = 68。
Question 2用直式計算。
92 ÷ 2 =
Answer and explanation
答案：92 ÷ 2 = 46
為甚麼？由最高位開始除：9 ÷ 2 = 4 餘 1；12 ÷ 2 = 6。所以 92 ÷ 2 = 46。
Question 3用直式計算。
470 ÷ 5 =
Answer and explanation
答案：470 ÷ 5 = 94
為甚麼？由最高位開始除：4 不夠 5 除，連同下一位一起除；47 ÷ 5 = 9 餘 2；20 ÷ 5 = 4。所以 470 ÷ 5 = 94。
Question 4用直式計算，寫出商和餘數。
759 ÷ 9 = …
Answer and explanation
答案：759 ÷ 9 = 84 … 3
為甚麼？由最高位開始除：7 不夠 9 除，連同下一位一起除；75 ÷ 9 = 8 餘 3；39 ÷ 9 = 4 餘 3。所以 759 ÷ 9 = 84 … 3。餘數 3 要小於除數 9。
Based on learning unit 3N3 of the Education Bureau’s Primary Mathematics Curriculum (2017).