This week we started learning about algebra – using pronumerals in equations to represent numbers. Algebra is very useful for writing relationships between numbers. For example, if the cost of an adult movie ticket is “A” and the cost of a child’s ticket is “C”, then if we take 2 adults and 3 children to the movies, the total cost will be 2A + 3C. We substitute the value of each ticket into the equation.  There are several rules when we use algebra – we leave out the multiplication sign and always write the number before the pronumeral. If there is no number before the pronumeral, that means ‘one multiplied by’ the pronumeral (we leave the 1 out).

Algebra is also useful for representing number patterns – the number of rails in a fence, the number of chairs around tables or the number of matches in a pattern of rectangles. One of my students asked “Why do we need to know algebra? My mum said she can’t do it!” Well, my response was that she does algebra every day without even knowing it! When baking, we double the recipe. So, we multiply every amount (butter, sugar, eggs, flour and milk) by two. When buying petrol, we need to multiply the amount of petrol by the cost per litre. If it costs $60.00 to fill the tank, how much does it cost for half a tank of petrol? When calculating a taxi fare we need to add the flagfall (cost for hiring the cab) to the cost per kilometre, multiplied by the number of kilometres travelled. What other professions use algebra?