Page 34 - 新思维数学学生用书9 样章

2.3 Expressions and indices

Think like a mathematician

3 Arun, Sofia and Zara simplify the expression x ÷ x .
2
2
Read what they say.

I think the
answer is 1.

I think the
answer is 0.

I think the
answer is x.

a What do you think?
Do you agree with Arun, Sofia, Zara or none of
them? Tip
b Discuss your answer with other learners in the class. You could try

c Following your discussions, write down the correct different values
simplified expression for x ÷ x . for x and work
2
2
d What can you say about the answers when you out numerical
simplify these expressions? answers first.
x ÷ x y ÷ y a ÷ a c ÷ c d
4
5
b
4
b
d
5
Explain your answer.
4 This is part of Kai’s homework.
Use Kai’s method to simplify these expressions: Question
a 3x × 2x 3 Simplify the expression 6x × 3x .
2
4
2
b 4y × 3y 5 Answer
4
c 6z × 5z 5 6x × 3x = 6 × x × 3 × x 4
4
2
2
2
d 2m × 2m 3 = 6 × 3 × x × x 4
2
4
e 4n × n 7 = 18 × x 2+4
6
f p × 8p = 18 x 6
2

33