How To Teach Pupils To Write Algebraic Formulae

Hi, my name's Brooke and in this video we'll be looking at how algebra is used when writing formula. Now, a formula is a way of expressing a rule or relationship by using letters to represent variables. And describing a relationship using words is something that pupils are already doing quite naturally. For example, if we take a car park and we ask the pupils to work out the number of tires, they'd be able to tell you that you simply need to multiply the number of cars by 4 and this can be represented by t equals 4c. So the number of tyres can be found by multiplying the number of cars by 4. Let's have a look at another example. Leaks are us, our call out charge is £25. We then charge another £15 per hour. So we need to write a formula to show the total cost of, of calling out the plumber. Now, the first thing that we need to do is identify the variables. And in this case the variables are the total cost of calling out the plumber, which I'm going to represent with a C, and also the number of hours worked, which I'm going to use a H to represent. The next thing that we need to do is describe this relationship using words. So here I've got the total cost is equal to 15 times the number of hours PL plus the 25 pound call out charge. Once this relationship has been described using words, it's much easier to describe it algebraically. So, for example, C, the total cost is equal to 15 times the number of hours plus the 25 pounds call out charge. So C equals 15H25. Now, the final step is to make sure that you explain what these letters mean. So C means the total cost and H means the number of hours worked. And that's how you use algebra when writing formulas.