With coordinates, I believe the two most common errors are the scale of the axis and confusing the x and y coordinate. This task focuses on the former, using just a section of a grid between different values such that pupils can't mix up x and y.
Part 1 of the task focuses on plotting coordinates on minimally different sections of a grid, where pupils' attention will be drawn to the scale.
Part 2 pupils are given a plotted point and must find its coordinates. As the questions progress pupils are required to generalise, with f being a particular challenge. Depending on your class you may want to edit these questions. One way that may be more suitable is to delete d, e, and f, and change them to what do you notice, what other values of a and b could we try to explore this pattern. If you do want to stick with the algebraic route them perhaps 10p and 10q would work better, I haven't decided yet, I would love to know your thoughts.
Part 3, facilitates learner-generated questions and allows for a more open task that could be extended.
Hopefully, this resource will be of some use to you. I would love to hear feedback either constructive or positive.