Page 4 - 新思维数学活动用书9 样章

How to use this book

How to use this book

This workbook provides questions for you to practise what you have

learned in class. There is a unit to match each unit in your Learner’s Book.

Each exercise is divided into three parts:
• Focus: these questions help you to master the basics

• Practice: these questions help you to become more confident in
2.6 Deriving and using formulae
using what you have learned
2.6 Deriving and using formulae 1 Number and
• Challenge: these questions will make you think very hard.
calculation
You will also find these features:
Exercise 2.6 Key words
1.1 Irrational numbers
Words you need to know. changing the
Focus subject
Exercise 1.1
1 You already know a lot of mathematical formulae. subject of a Key words
Match each rectangular card with the correct oval card. formula irrational number
Focus
surd
1 Copy this table. Tick (✓) the correct boxes.
A Area of a triangle B Volume of a cuboid Number Rational Irrational
36
48
D Circumference of a circle
C Area of a parallelogram These questions help 64
you to practise thinking 84
E Area of a trapezium F Area of a circle 3 100
and working 2 Look at these numbers:
12.77 −36 27 500 12 61 − 8
3
mathematically.
=
i A = π r 2 ii A bh iii C = π d a Write the irrational numbers.
b Write the integers.
3 Write whether each of these numbers is an integer or a surd.
a 25 b 3 25 c 125
e
d
f
3
225
225
3
125
1
iv V = lbh v A = 1 bh vi A = ( a + b h 4 Is each of these numbers rational or irrational? Give a reason for each answer.
)
2 2
a 3 + 6 b 3 + 6 c 64 + 3 64 d 3 8 + 3 19
2 a Work out the number of hours in
i 1 day ii 2 days
iii 3 days iv d days.
b The formula to work out the number of hours (H) in d days
is H = 24d. Tip 5
Copy and complete the working to find the number of hours Substitute d = 10
into the formula.
in 10 days. 01-SJ00079325 新思维数学 活动用书9（正文p5-10）-2校_DO.indd 5 2022/7/13 16:33:05
H = 24d = 24 × d = 24 × 10 =
3 a Work out the number of days in
i 1 week ii 2 weeks
iii 3 weeks iv w weeks.
b Copy and complete the formula to work out the number of days (D) in w weeks: D = ……
Use your formula to find the number of days in 8 weeks. 3
4 a Work out the total number of days in
i 1 week and 2 days ii 3 weeks and 4 days
iii w weeks and d days.

31

02-SJ00079325 新思维数学 活动用书9（正文p11-34）-2校_DO.indd 31 2022/7/13 16:33:47