What is subtraction? 什么是减法
What are square and cube numbers 什么是平方和立方?
这节课共4个模块：
- Keywords 关键词
- key concepts 关键概念
- Video 教学视频
- Quiz 练习
What is square number?
关键词汇和句型
square '平方',
cube '立方',
multiply '乘以',
power 'n次方'.
2² is the same as 'the power of 2'.
3² is the same as 'the power of 3'.
4² is the same as 'the power of 4'.
Square numbers
A square number 平方数 is a number multiplied by itself 自己乘以自己. This can also be called ‘a number squared’ 平方数. The symbol 符号 for squared is ².
2² = 2 x 2 = 4
3² = 3 x 3 = 9
4² = 4 x 4 = 16
5² = 5 x 5 = 25
The square numbers up to 100 are: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100
cube '立方' = the power of 3
2³ = 2 × 2 × 2 = 8
3³ = 3 × 3 × 3 = 27
4³ = 4 × 4 × 4 = 64
5³ = 5 × 5 × 5 =125
Cube numbers
A cube number 立方数 is a number multiplied by itself twice 两次. This can also be called ‘a number cubed’ 立方数. The symbol for cubed is ³.
2³ = 2 × 2 × 2 = 8
3³ = 3 × 3 × 3 = 27
4³ = 4 × 4 × 4 = 64
5³ = 5 × 5 × 5 =125
The cube numbers up to 100 are: 1, 8, 27, 64
