Ronald Hui Tak Sun Secondary School Mathematics Ronald Hui Tak Sun Secondary School

Reminder Standard Homework 0-B1 Standard Homework 0-C1 Deadline: 18 Sep (Mon) Standard Homework 0-C1 Deadline: 21 Sep (Thu) Standard Quiz (Chapter 0) Folder Checking Next week after Quizzes Ronald HUI

Revision Prime numbers (質數) Multiples (倍數) Factors (因子) 2, 3, 5, 7, 11, 13, 17, 19, 23, … Multiples (倍數) Multiples of 2: 2, 4, 6, 8, … Multiples of 3: 3, 6, 9, 12, … Factors (因子) 2 is a factor of 2, 4, 6, 8, … 3 is a factor of 3, 6, 9, 12, … Ronald HUI

Revision Factors of 18: 1, 2, 3, 6, 9, 18 18 = 2 x 9 = 2 x 3 x 3 Prime factors of 18: 2, 3 18 = 2 x 9 = 2 x 3 x 3 18 = 2 x 32  Index Notation 32 = 3 x 3 (指數記數法) 3 is base 底 2 is index 指數 Ronald HUI

Revision Index notation is very helpful in long expression of prime factors 432 = 2 x 2 x 2 x 2 x 3 x 3 x 3 = 24 x 33 86400 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 3 x 3 x 3 x 5 x 5 = 27 x 33 x 52 Ronald HUI

Revision We can find H.C.F. from Index Notation! (用指數記數法找HCF) 18 = 2 x 3 x 3 = 2 x 32 24 = 2 x 2 x 2 x 3 = 23 x 3 We know H.C.F. of 18 and 24 is 6 6 = 2 x 3 Can you find the rule? Ronald HUI

Revision We can find L.C.M. from Index Notation! (用指數記數法找LCM) 6 = 2 x 3 = 2 x 3 We know L.C.M. of 4 and 6 is 12 12 = 2 x 2 x 3 = 22 x 3 Can you find the rule? Ronald HUI

Revision If the numbers did not have common prime factors, their HCF is 1 and their LCM is the product of them 20 = 22 x 5 63 = 32 x 7 Their HCF is 1 Their LCM is 20 x 63 = 1260 Ronald HUI

Fractions (p.11) Fractions 3 over 4 3 is divided by 4 3  4  Numerator (分子)  Fraction line (分數線)  Denominator (分母) 3 over 4 3 is divided by 4 3  4 Three-quarter (quarter = ¼) Ronald HUI

Fractions (p.12) Types of Fractions Proper fraction (真分數) Improper fraction (假分數) Mixed fraction (帶分數) http://zh.wikipedia.org/zh-hk/%E5%88%86%E5%BC%8F#.E5.88.86.E9.A1.9E Ronald HUI

Comparing Fractions The following fractions are equal We can then compare different fractions Ronald HUI

Addition, Subtraction Use improper fractions Change to same denominators Do operations on numerators LCM of 3, 2, 4 is 12 Ronald HUI

Multiplication, Division Use improper fractions Use reciprocal for division Multiply numerators and denominators separately Simplest Form! Ronald HUI

Time for Practice Pages 0.22 of Textbook 1A Questions 2 – 12 Ronald HUI

Revision for Quiz Textbook 1A Chapter Summary My PowerPoint files Pages 0.2 – 0.29 Chapter Summary Pages 0.24 – 0.25 My PowerPoint files http://personal.tsss.edu.hk/roh Your own notes!!! Ronald HUI

Enjoy the world of Mathematics! Good Luck! Enjoy the world of Mathematics! Ronald HUI