Notes on capture mark, release and recapture population estimates, suitable for courses including A-level biology and Edexcel GCSE statistics. Covering one page, the assumptions and the idea of a reciprocal are explained and there’s two model calculations.

Worksheet and worked examples with two intuitive stories of how people could need to use a reciprocal to find a whole quantity when they only know a fraction of it. Could be suitable for KS2, KS3 or advanced KS1 students. There’s versions in poster form, a problem sheet and (probably most useful for students) a version with notes and worksheet merged onto one page. (The answers are 30 minutes and 12 minutes.) To make it approachable for students in a range of countries I have versions where the money is UK pounds, the Euro or dollars-with appropriate Emoji images! Comment if you’d like a version in a different currency, I’ll add it.

Revision notes on trigonometry: all the equations with all the rearrangements. Covers trigonometry of a right angle triangle, the sine rule and the cosine rule. Also explains when you can use the sine and cosine rule equations (e.g. that you can work out an angle using the cosine rule when you know all the sides). Suitable for all the GCSE maths specifications.