Percentages (I)
Percentages on a hundred square, showing one amount as so many hundredths of another; reading and writing percentages and the per cent sign (%); 100% as the whole; changing percentages into decimals and fractions and back; and comparing percentages, decimals and fractions.
Key words
| Chinese | English |
|---|---|
| 百分數 | percentage |
| 百分號 | per cent sign (%) |
| 百分之幾 | what per cent |
| 全部 | whole |
The 7 short lessons and the chapter test
Lessons are in Chinese for now.
- 認識百分數
- 讀寫百分數
- 百分數和小數
- 百分數和分數
- 比較大小
- 重溫
- 綜合練習
- 章節測驗 (chapter test)
Sample questions (in Chinese)
Question 1大正方形平均分成 100 個小正方形。塗色部分佔大正方形的百分之幾？
%
Answer and explanation
答案：31%
為甚麼？塗色的小正方形有 31 個，即是 31100 = 31%。
Question 2某校有 20% 學生乘巴士上學。不是乘巴士上學的學生佔全校的百分之幾？
%
Answer and explanation
答案：80%
為甚麼？全校學生是 100%。100% − 20% = 80%。
Question 3把百分數化為小數。
223% =
Answer and explanation
答案：223% = 2.23
為甚麼？223% = 223 ÷ 100，即是把小數點向左移兩個位：223% = 2.23。
Question 4把小數化為百分數。
1.77 = %
Answer and explanation
答案：1.77 = 177%
為甚麼？小數乘以 100%，即是把小數點向右移兩個位：1.77 = 1.77 × 100% = 177%。
Based on learning unit 6N3 of the Education Bureau’s Primary Mathematics Curriculum (2017).