Page 26 - 新思维数学学生用书6 样章
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2.2 Special numbers
2.2 Special numbers
We are going to …
• work out the square number in any position, for example, the ninth square
number is 9 × 9 = 81
• use the notation to represent squared
2
• know the cube of numbers up to 5, for example, 5 = 5 × 5 × 5 or 5 × 5
2
3
which is 125.
Have you ever tried to solve the Rubik’s cube puzzle?
cube number
square number
How many small cubes make up the large cube?
In this section you will learn about cube numbers. A square number is a number you
get when you multiply an integer by itself. A cube number is a number you get when
you multiply an integer by itself and by itself again. 2 means 2 squared, which equals
2
the square number 4.
2 means 2 cubed, which equals the cube number 8.
3
Worked example 2
Which is larger?
2 or 3 2
3
Explain your answer.
Answer: 3 > 2 3 Explain your answer by showing the calculations for
2
2 = 2 × 2 × 2 = 8 2 and 3 .
3
3
2
3 = 3 × 3 = 9 9 > 8
2
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