We like to introduce algrebra to the children towards the end of P7 so they have some understanding of it before they go to their next school where it will be covered in a lot more depth.  Watch the Corbettmaths video and the children then need to calculate the value of each letter on the Alphabet Algebra worksheet.  They are already given the value of the two of the letters: D and K.  They should write what numbers they represent in the third column, e.g. D = 6.  Once they have done those two, they need to work out the rest of the letters.  For example, they can quickly work out that the value of B is 9 because it says B = D + 3 so if we know D is equal to 6 then 6 + 3 = 9.  The second column can be used to do any working they want to do.