The week that was (no. 15)

Well we’ve made it to December. For me the term has flown by and I’m not sure I achieved many of the things I wanted to – but what’s new? This week was S2 Parents Evening. I always enjoy chatting to parents about their child and getting a chocolate biscuit from the S6 helpers.

This week my classes have been working on:

  • S2 drawing and interpreting graphs, ratio
  • S3 expanding double brackets including quadratic factors
  • N5 angles, perpendicular bisectors, 3d Pythagoras
  • AH Maclaurin series

Method of the week

Expanding brackets with my S3 class this week reminded me how much I love using a grid rather than FOIL. The structure allows pupils to see clearly what to do and they can adapt the grid to expand different sizes of brackets.

We started off expanding brackets like (x + 2)(x + 3), (x – 4)(x – 5), (x + 7)(x – 8). Very quickly many were able to expand brackets like (2x + 5)(3x – 7). There were the usual problems when it came to simplifying the x term. Pupils struggling with negative numbers, thinking -3x + -4x = 7x as two negatives make a positive. This did lead to some positive conversations about using a number line. On an encouraging note, there were some pupils who expanded brackets like (x2 + 2x – 6)(x2 – 4x – 7) without direct explanation as they knew just to expand the grid.

Answer of the week

While tackling Maclaurin expansions I was pleased to see the different way a pupil solved this problem.

I assumed that they would use the chain rule to differentiate f(x) then continue. However, one pupil chose to find the Maclaurin series for y = sinx then multiply the series by itself to get y = sin2x. It’s always nice to see pupils thinking differently from yourself.

Numeracy of the week

I had a cover class in Home Economics. It was for N5 Hospitality. The class were writing time plans for cooking their three recipes for their prelim. This is essentially a problem solving task trying to fit in different stages of the recipes in appropriate times so that the dishes were all served on time. I was amazed/concerned about how difficult many of them found it. I will definitely be thinking about how I can build in skills to help as part of our maths courses.

Questions of the week

I introduced the concept of ratio to my S2 class this week and wanted to focus on simplifying first. I knew they wouldn’t need an excessive number of practice questions so I set this from Increasingly Difficult Questions by @Taylorda01

ratioWhat I love about the question sequence is the increase in numerical difficulty, the need to convert between different units and the link to algebra. I’m not sure I have ever written a ratio question involving algebra. 


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