TOPIC: 3 ALGEBRA OUTCOMES: Stage 4: PAS 4·1 Uses letters to represent numbers and translates between words and algebraic symbols (p82) PAS 4·2 Creates, records, analyses and generalises number patterns using words and algebraic symbols in SUGGESTED TIME: a variety of ways. ( p83) PAS 4·3 Uses the algebraic symbol system to simplify, expand and factorise simple algebraic expressions (p85) Stage 5: PAS 5·1·1 Applies the index laws to simplify algebraic expressions (p87) CONTENT Key Ideas for Stage 4 1. Use letters to represent numbers 2. Translate between words and algebraic symbols and between algebraic symbols and words 3. Recognise and use simple equivalent algebraic expressions. 4. Create, record and describe number patterns using words 5. Use algebraic symbols to translate descriptions of number patterns 6. Represent number pattern relationships as points on a grid. 7. Use the algebraic symbol system to simplify, expand and factorise simple algebraic expressions 8. Substitute into algebraic expressions PAS 5.2.1 Simplifies, expands and factorises algebraic expressions involving fractions and negative and fractional indices(p 88) KNOWLEDGE AND SKILLS RESOURCES TERMINOLOGY Pronumeral Knowledge and Skills Sum Maths Works 9 Int Students learn about Product Ch 5 using a process that consists of building a geometric Simplify Ch 7 p252 – 253 pattern, completing a table of values, describing the Expand P260 – 261 pattern in words and algebraic symbols and Factorise representing the relationship on a graph: Substitute New Coarse Maths - modelling geometric patterns using materials such as Grouping symbols Yr9 Adv matchsticks to form squares Like terms Ch2 Algebraic expression eg , , , ,… Ch 6 p168 – 172 Notation - describing the pattern in a variety of ways that relate Quotient New Century Maths to the different methods of building the squares, and Variables Int 9 recording descriptions using words Ch 3, Ch 5 - forming and completing a table of values for the geometric pattern New Century Maths Number of eg Yr 9 Adv 1 2 3 4 5 10 100 squares Ch 3, Ch 5 Number of matchsticks 4 7 10 13 _ _ _ - representing the values from the table on a number grid and describing the pattern formed by the points on the graph (note – the points should not be joined to form a line because values between the points have no meaning) - determining a rule in words to describe the pattern from the table – this needs to be expressed in function form relating the top-row and bottom-row terms in the table - describing the rule in words, replacing the varying number by an algebraic symbol Heathcote High School 106738440 Maths Works 10 Int Ch 3 p 79 – 102 Mathscape Yr 9 Stage 5·2 Ch 2, Ch 8 Mathscape Yr 9 Stage 5·3 Ch 2, Ch 9 Page 1 of 5 - using algebraic symbols to create an equation that describes the pattern - creating more than one equation to describe the pattern - using the rule to calculate the corresponding value for a larger number using a process that consists of identifying a number pattern (including decreasing patterns), completing a table of values, describing the pattern in words and algebraic symbols, and representing the relationship on a graph: - completing a table of values for the number pattern eg a 1 2 3 4 5 10 100 b 4 7 10 13 _ _ _ - describing the pattern in a variety of ways and recording descriptions using words - representing the values from the table on a number grid and describing the pattern formed by the points on the graph determining a rule in words to describe the pattern from the table – this needs to be expressed in function form relating the top-row and bottom-row terms in the table describing the rule in words, replacing the varying number by an algebraic symbol WORKING MATHEMATICALLY ask questions about how number patterns have been created and how they can be continued (Questioning) using algebraic symbols to create an equation that describes the pattern creating more than one equation to describe the pattern using the rule to calculate the corresponding value for a larger number recognising like terms and adding and subtracting like terms to simplify algebraic expressions eg 2n 4m n 4m 3n recognising the role of grouping symbols and the different meanings of expressions, such as 2a 1 and 2a 1 Heathcote High School 106738440 Page 2 of 5 simplifying algebraic expressions that involve multiplication and division 12a 3 eg 4x 3 2ab 3a simplifying expressions that involve simple algebraic fractions eg a a 2 3 2x x 5 3 expanding algebraic expressions by removing grouping symbols (the distributive property) 3( a 2) 3a 6 eg 5( x 2) 5 x 10 a ( a b) a 2 ab factorising a single term eg 6ab 3 2 a b factorising algebraic expressions by finding a common factor eg 6a 12 6(a 2) x 2 5 x x( x 5) 5ab 10a 5a(b 2) 4t 12 4(t 3) distinguishing between algebraic expressions where letters are used as variables, and equations, where letters are used as unknowns substituting into algebraic expressions generating a number pattern from an algebraic expression eg x 1 2 3 4 5 6 10 100 x3 4 5 6 _ _ _ _ _ replacing written statements describing patterns with equations written in algebraic symbols eg ‘you add five to the first number to get the second number’ could be replaced with ‘ y x 5 ’ translating from everyday language to algebraic language and from algebraic language to everyday language Heathcote High School 106738440 Page 3 of 5 Key Ideas for Stage 5·1 1. Apply the index laws to simplify algebraic expressions (positive integral indices only) using the index laws previously established for numbers to develop the index laws in algebraic form eg 2 2 2 3 2 2 3 2 5 a m a n a mn 2 5 2 2 2 5 2 2 3 a m a n a mn 2 2 (a m ) n a mn 2 3 6 WORKING MATHEMATICALLY DIAGNOSIS/ASSESSMENT verify the index laws using a calculator eg use a calculator to compare the values of (34 ) 2 and 38 (Reasoning) establishing that a0 1 using the index laws eg a3 a3 a33 a0 and a3 a3 1 a0 1 simplifying algebraic expressions that include index notation eg 5x 0 3 8 2 x 2 3x 3 6 x 5 12a 6 3a 2 4a 4 2m 3 (m 2 3) 2m 5 6m 3 Key Ideas for Stage 5·2 simplifying algebraic expressions involving fractions, such as 2x 2x 5 3 7 a 5a 8 12 2y y 3 6 2ab 6 3 2b Simplify, expand and factorise algebraic expressions including those involving fractions or with negative and/or fractional indices applying the index laws to simplify expressions involving pronumerals establishing that a 2 a a a a a2 a WORKING MATHEMATICALLY state whether particular equivalences are true or false and give reasons eg Are the following true or false? Why? 5x 0 1 9 x 5 3x 5 3x a5 a7 a 2 1 2c 4 4 2c (Applying Strategies, Reasoning, Communicating) Heathcote High School 106738440 Page 4 of 5 using index laws to assist with the definition of the fractional index for square root a a 2 given 2 1 and a 2 a 1 a a2 then using index laws to assist with the definition of the fractional index for cube root using index notation and the index laws to establish that a 1 1 1 1 , a 2 2 , a 3 3 , … a a a applying the index laws to simplify algebraic expressions such as (3 y 2 ) 3 4b 5 8b 3 9 x 4 3x 3 1 1 3 x 2 5 x 2 1 1 6 y 3 4 y 3 expanding, by removing grouping symbols, and collecting like terms where possible, algebraic expressions such as 2 y ( y 5) 4( y 5) 4 x(3x 2) ( x 1) 3x 2 (5 x 2 2 xy ) factorising, by determining common factors, algebraic expressions such as 3x 2 6 x 14ab 12a 2 21xy 3x 9 x 2 Heathcote High School 106738440 Page 5 of 5