form 1 mathematics chapter 2 and chapter 4. ronald hui when we work on the followings, we should...
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Form 1 MathematicsChapter 2 and Chapter 4
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 + 6B2. A -2B –3A +4B = A -3A -2B +4B
= (A-3A) + (-2B+4B)= (-2A) + (2B)= -2A +2B
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 = bThen a + c = b + c
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 = bThen a - c = b - c
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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 = bThen ac = bc
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Division of equality ( 等量相除 ) 5X = 20
5X 5 = 20 5 X = 4
5X = 20 X = 20 5 X = 4
If a = bThen a c = b c(but c 0)
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Distributive Law ( 分配律 ) 5 (X+2) = 205 (X) + 5 (2) = 20
5X+10 = 20 5X = 10
X = 2
a(b + c) = ab + ac(a + b)c = ac + bc
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
Ronald HUI
Cross Method ( 交义相乘 )
If a c = b dThen ad = bc(but c0 and d0)
15
28
2815
47355
7
4
3
x
x
x
x
Page 94 of Textbook 1A◦ Class Practice
Page 94 of Textbook 1A◦ Questions 16, 19, 22
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 )
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) = 69x + x +1 + x + 2 = 69x + x + x + 1 + 2 = 69
3x = 66 => x = 22.
So, the numbers are 22, 23 and 24.
Page 99 of Textbook 1A◦ Questions 3 – 9
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!
Good Luck!
Enjoy the world of Mathematics!
Ronald HUI