Mathematics Ronald Hui Tak Sun Secondary School

Ronald HUI Mathematics What have you learnt last week? What have you learnt last week? Have you handed in the following homework? Have you handed in the following homework? Summer Revision P6 – S1 Summer Revision P6 – S1 One missing One missing Standard Homework (I) Standard Homework (I) Two missing Two missing

Ronald HUI My Mathematics class Keep silence in the class Keep silence in the class No talking when I talk No talking when I talk Make your only notes Make your only notes Deadline is deadline Deadline is deadline Late homework  detention Late homework  detention Do corrections! Do corrections! Re-test / Re-dictation Re-test / Re-dictation

Ronald HUI Revision Arithmetic Operations (Chapter 0.2, p.2 – 4) Arithmetic Operations (Chapter 0.2, p.2 – 4) “+” – Addition Plus “+” – Addition Plus “–” – Subtraction Minus “–” – Subtraction Minus “x” – Multiplication Times “x” – Multiplication Times “  ” – Division Is divided by “  ” – Division Is divided by

Ronald HUI Calculation order Please follow the order: Please follow the order: Brackets ( ), [ ], { } ( 小中大括號 ) Brackets ( ), [ ], { } ( 小中大括號 ) Multiplication / division first, then addition / subtraction ( 先乘除後加減 ) Multiplication / division first, then addition / subtraction ( 先乘除後加減 ) From left to right ( 由左至右 ) From left to right ( 由左至右 )

Ronald HUI Time for Practice Page 3 of Workbook 1A Page 3 of Workbook 1A Exercise (Level 2) Exercise (Level 2) Questions 5 – 6 Questions 5 – 6

Ronald HUI Multiples (p.7) Multiples ( 倍數 ) Multiples ( 倍數 ) Multiples of 2:2, 4, 6, 8, … Multiples of 2:2, 4, 6, 8, … Multiples of 3:3, 6, 9, 12, … Multiples of 3:3, 6, 9, 12, … Multiples of 4:4, 8, 12, 16, … Multiples of 4:4, 8, 12, 16, … Multiples of 5:5, 10, 15, 20, … Multiples of 5:5, 10, 15, 20, … Multiples of 6:6, 12, 18, 24, … Multiples of 6:6, 12, 18, 24, … What is the rule? What is the rule?

Ronald HUI Multiples (p.7) How many multiples of 2 do we have? How many multiples of 2 do we have? Is there any number having limited number of multiples? Is there any number having limited number of multiples? Is 0 a multiple of 2? Is 0 a multiple of 2? Normally, multiples are used on natural numbers only Normally, multiples are used on natural numbers only

Ronald HUI Factors (p.8) 4 is a multiple of 2  2 is a factor ( 因子 ) of 4. 4 is a multiple of 2  2 is a factor ( 因子 ) of 4. Factors Factors 2 is a factor of 2, 4, 6, 8, … 2 is a factor of 2, 4, 6, 8, … 3 is a factor of 3, 6, 9, 12, … 3 is a factor of 3, 6, 9, 12, … 4 is a factor of 4, 8, 12, 16, … 4 is a factor of 4, 8, 12, 16, … 5 is a factor of 5, 10, 15, 20, … 5 is a factor of 5, 10, 15, 20, … What is the rule? What is the rule?

Ronald HUI Factors (p.8) Find all factors of 18. Find all factors of  1 = 18  1 is a factor 18  1 = 18  1 is a factor 18  2 = 9  2 is a factor 18  2 = 9  2 is a factor 18  3 = 6  3 is a factor 18  3 = 6  3 is a factor 18  4 = ?  4 is NOT a factor 18  4 = ?  4 is NOT a factor 18  5 = ?  5 is NOT a factor 18  5 = ?  5 is NOT a factor 18  6 = 3  6 is a factor 18  6 = 3  6 is a factor 18  7 = ?  7 is NOT a factor 18  7 = ?  7 is NOT a factor

Ronald HUI Factors (p.8) Find all factors of 18. Find all factors of = 1 x = 1 x = 2 x 9 18 = 2 x 9 18 = 3 x 6 18 = 3 x 6 18 = 6 x 3 18 = 6 x 3 18 = 9 x 2 18 = 9 x 2 18 = 18 x 1 18 = 18 x 1 Factors of 18: 1, 2, 3, 6, 9, 18 Factors of 18: 1, 2, 3, 6, 9, 18

Ronald HUI Factors (p.8) Factors of 18: 1, 2, 3, 6, 9, 18 Factors of 18: 1, 2, 3, 6, 9, 18 Any number is divisible by 1 Any number is divisible by 1 1 is a factor of any number 1 is a factor of any number Even numbers are divisible by 2 Even numbers are divisible by 2 2 is a factor of any even number 2 is a factor of any even number Any number is divisible by itself Any number is divisible by itself Any number is a factor of itself Any number is a factor of itself

Ronald HUI Prime Numbers (p.8) Prime number ( 質數 ) Prime number ( 質數 ) A natural number (other than 1) which is NOT divisible by any number except 1 and itself A natural number (other than 1) which is NOT divisible by any number except 1 and itself Prime number: Prime number: 2, 3, 5, 7, 11, 13, 17, 19, 23, … 2, 3, 5, 7, 11, 13, 17, 19, 23, … Composite number ( 合成數 ) Composite number ( 合成數 ) 4, 6, 8, 9, 10, 12, 14, 15, 16, … 4, 6, 8, 9, 10, 12, 14, 15, 16, … 1 is not prime nor composite 1 is not prime nor composite

Ronald HUI Reminder BCA Online Exercise BCA Online Exercise Deadline: 10 Sep (Mon) Deadline: 10 Sep (Mon) Re-dictation (11 Sep) Re-dictation (11 Sep) Pages 2 – 3 of Textbook Pages 2 – 3 of Textbook Standard Homework (II) Standard Homework (II) Deadline: 14 Sep (Fri) Deadline: 14 Sep (Fri) PowerPoint files PowerPoint files

Ronald HUI Good Luck! Enjoy the world of Mathematics!