Form 1 Mathematics Chapter 2 and Chapter 4

Ronald HUI  “>”: Greater than  “<”: Less than  “  ”: Greater than or equal to (or Not less than) ◦ A combination of “>” and “=”  “  ”: Less than or equal to (or Not greater than) ◦ A combination of “<“ and “=”

Ronald HUI  P.166 Question 9: Add 5 to 4 times of a number p and the sum is greater than 33.  Add 5  “+5”  4 times of a number p  “4p”  The sum  “4p+5”  Then, the inequality is  “4p+5 > 33”

Ronald HUI  P.166 Question 11: When the sum of a number s and 3 is multiplied by 2, the product is smaller than -10.  The sum of s and 3  “s+3”  Multiplied by 2  “  2”  The product  “(s+3)  2” or 2(s+3)  The inequality is  “2(s+3) < -10”  Write 3 numbers  by guessing!

Ronald HUI  P.166 Question 13a: Mike has 2 packs of $1.9 stamps, 1 pack of $2.4 stamps and y packs of $1.4 stamps. Each pack contains 10 pieces of stamps. Write an inequality…  2 packs of $1.9  2  $1.9  10 = $38  1 pack of $2.4  1  $2.4  10 = $24  y packs of $1.4  y  $1.4  10 = $14y  Total value  $38+$24+$14y  The inequality is  $38+$24+$14y <$100 or 14y+62 < 100

Ronald HUI  P.166 Question 13b: Find the value of y if the total value of the stamps that Mike has is $76.  Total value  $38+$24+$14y  The equation is  $38+$24+$14y = $76 or 14y+62 = 76 14y = 14 y = 1  Therefore, y = 1.  or “Mike has one pack of $1.4 stamps.”

Ronald HUI  Some special terms:  One half = 二分之一  One third = 三分之一  One quarter / One fourth = 四分之一  One fifth = 五分之一  First, Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth, Ninth, Tenth, Eleventh, Twelfth, Thirteenth, Fourteenth, …

 Page 165 of Textbook 1A ◦ Questions  Page 77 of WB 1A  Homework ◦ Questions 1 - 4

Ronald HUI  A formula is an equation with ◦ At least 1 variables on the right of equal sign. ◦ Only 1 variable (Subject) on the left of equal sign.  e.g. A = (U + L)  H  2 ◦ A is the subject of the formula ◦ U, L and H are the variables of the formula  Do you know what this formula means?

Ronald HUI  P.169 Question 18: v = u + gt (u = -8, g = 10, t = 3, v = ?)  v = u + gt  = (-8) + (10) (3)  Method of substitution  =  = 22

Ronald HUI  P.169 Question 20: In the formula S=88+0.5t, if S=120, find the value of t. S = t (120) = t = 0.5t 32 = 0.5t 32  2 = t 64 = t t = 64

Ronald HUI  P.169 Question 22a: It is given that V=Ah  3. If V = 40 and h = 6, find the value of A. V = Ah  3 (40) = A (6)  3 40  3 = 6A 120 = 6A 120  6 = A 20 = A A = 20

Ronald HUI  P.169 Question 22b: It is given that V=Ah  3. Find the value of h such that A = 5 and the value of V is half of that given in (a)  In (a), V = 40. So, in (b), V = 20. V = Ah  3 (20) = (5) h  3 20  3 = 5h 60 = 5h 60  5 = h h = 12

 Page 169 of Textbook 1A ◦ Questions  Pages of WB 1A  Homework ◦ Questions 1 - 5

Ronald HUI  Consider a sequence: 2, 4, 6, 8, 10, …  Can you guess what are the next numbers?  What is the 10 th term?  What is the 100 th term?  What is the n th term?  1, 2, 3, 4, 5, …, 10, …, 100, …, n ( 第幾個 )  2, 4, 6, 8, 10, …, 20, …, 200, …, 2n ( 答案 )

Ronald HUI  A Sequence is a group of numbers with number pattern.  Each number in the sequence is called a Term.  The first one in the sequence is called the First Term.  In the sequence, 2, 4, 6, 8, 10, …  2 is the first term, 4 is the 2 nd term, 6 is …  The general term ( 通項 ) is 2n or a n =2n

Ronald HUI  What is the NEXT TWO terms of the following sequences?  4, 8, 12, 16, 20, …  12, 24, 36, 48, 60, …  -1, -2, -3, -4, -5, …  5, 6, 7, 8, 9, …  6, 8, 10, 12, 14, …  -20, -10, 0, 10, 20, …

Ronald HUI  What is the GENERAL terms of the following sequences?  4, 8, 12, 16, 20, …  12, 24, 36, 48, 60, …  -1, -2, -3, -4, -5, …  5, 6, 7, 8, 9, …  6, 8, 10, 12, 14, …  -20, -10, 0, 10, 20, …

Ronald HUI  Given a general term: a n =2n-1  What is the first 5 terms?  The first 5 terms are: ◦ a 1 = 2(1)-1 = 1 ◦ a 2 = 2(2)-1 = 3 ◦ a 3 = 2(3)-1 = 5 ◦ a 4 = 2(4)-1 = 7 ◦ a 5 = 2(5)-1 = 9  What is the 17 th term?  The 17 th term is a 17 = 2(17)-1 = 33

 Pages of WB 1A ◦ Questions  Page 175 of Textbook 1A ◦ Questions

 Folder ◦ 13 Nov (Tuesday)  WB (P.77, 80, 81) ◦ 13 Nov (Tuesday)  SHW (III) (Chapter 4) ◦ 14 Nov (Wednesday)  Open Book Quiz (Chapter 4) ◦ 14 Nov (Wednesday)  Close Book Quiz (Chapter 4) ◦ 21 Nov (Wednesday)  You must hand in on time!

Good Luck! Enjoy the world of Mathematics! Ronald HUI