Dr Yeap Ban HarConsultant, New Syllabus Mathematics

Junyuan Secondary School,

Singapore

Victory Christian International School,

Manila

1st Block 4 x 2 x 12nd Block 4 x 2 x 33rd Block

10

10

76

x x x

x

10

10

76

x x x

x

10

10

76 – 20

King Solomon Academy,

London

King Solomon Academy,

London

Method 1

21 + 23 + 25 = 6919 + 21 + 23 = 6317 + 19 + 21 = 57

Method 2

Note that the mean of the three numbers is the middle number

57 : 3 = 19The other numbers are 17 and 21.

Method 3

Make a list 1, 3, 5, 7, 9, …, 15, 17, 19, 21, 23, 25, 27, …

Method 3

x

x

x

2

2 2

The numbers are 17, 19 and 21.

x cannot be a

negative value

because it is an

average speed.

Lesson 41 10.10.11

Lesson 41 10.10.11

ab To prove that angle at centre

is equal to 2a + 2b

a

Northbrooks Secondary School,

Singapore

Lesson 41 10.10.11

ab To prove that angle at centre

is equal to 2a + 2b

a

2a

180o - 2a

Lesson 41 10.10.11

ab To prove that angle at centre

is equal to 2a + 2b

a

2ab2b

Lesson 42 10.10.11

a b

In the case of this type of figures, where is the angle at centre?a

2a

b

2b