1. Form 1 Mathematics Chapter 2 and Chapter 4

2. Ronald HUI  When we work on the followings, we should put together the like terms and then simplify!  For examples: 1.A +2B +3A +4B= A +3A +2B +4B = 4A + 6B 2.A -2B –3A +4B= A -3A -2B +4B = (A-3A) + (-2B+4B) = (-2A) + (2B) = -2A +2B

3. Ronald HUI  Addition of equality ( 等量相加 ) X – 7 = 2 X -7 +7 = 2 +7 X = 9 X – 7 = 2 X = 2 +7 X = 9 If a = b Then a + c = b + c

4. Ronald HUI  Subtraction of equality ( 等量相減 ) X + 7 = 12 X +7 - 7 = 12 -7 X = 5 X + 7 = 12 X = 12 -7 X = 5 If a = b Then a - c = b - c

5. Ronald HUI  Multiplication of equality ( 等量相乘 ) X  5 = 4 X  5  5 = 4  5 X = 20 X  5 = 4 X = 4  5 X = 20 If a = b Then ac = bc

6. Ronald HUI  Division of equality ( 等量相除 ) 5X = 20 5X  5 = 20  5 X = 4 5X = 20 X = 20  5 X = 4 If a = b Then a  c = b  c (but c  0)

7. Ronald HUI  Distributive Law ( 分配律 ) 5 (X+2) = 20 5 (X) + 5 (2) = 20 5X+10 = 20 5X = 10 X = 2 a(b + c) = ab + ac (a + b)c = ac + bc

8. Ronald HUI  Distributive Law ( 分配律 ) -5 (X-2) = 20 (-5) (X) – (-5) (2) = 20 -5X+10 = 20 -5X = 10 X = -2 -a(b + c) = -ab - ac -a(b - c) = -ab + ac

9. Ronald HUI  Cross Method ( 交义相乘 ) If a  c = b  d Then ad = bc (but c  0 and d  0)

10.  Page 94 of Textbook 1A ◦ Class Practice  Page 94 of Textbook 1A ◦ Questions 16, 19, 22

11. Ronald HUI  Use a letter x to represent unknown number 設 x 為變數 ( 即想求的答案 )  Follow the question and form an equation 根據問題，製造算式  Solve for x 算出 x 的值  Write answer in words (with units!) 寫出答案 ( 包括單位 )

12. Ronald HUI  If the sum of 3 consecutive ( 連續 ) numbers are 69, find these numbers.  Let x be the smallest number. Then, x+1 and x+2 are the next 2 numbers  Then,x + (x+1) + (x+2) = 69 x + x +1 + x + 2 = 69 x + x + x + 1 + 2 = 69 3x = 66 => x = 22.  So, the numbers are 22, 23 and 24.

13.  Page 99 of Textbook 1A ◦ Questions 3 – 9

14.  Correction of SHW (I) – Orange ◦ 29 Oct (Monday)  WB P.39-40, 42-43 ◦ 29 Oct (Monday)  SHW (II) – Yellow ◦ 30 Oct (Tuesday)  Open Book Quiz ◦ 31 Oct (Wednesday)  Close Book Quiz ◦ 7 Nov (Wednesday)  You must hand in on time!

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