Direct and Inverse Proportions: https://www.toppr.com/guides/maths/direct-and-inverse-proportions/inversely-proportional/
Geogebra: https://www.geogebra.org/
Better Lessons Ratios and Rates: https://betterlesson.com/browse/master_teacher/1844/61744/144165/carla-seeger?from=breadcrumb_lesson
Calculate a ratio from two numbers excel guide: https://exceljet.net/formula/calculate-a-ratio-from-two-numbers
Wikipedia Ratios: https://en.wikipedia.org/wiki/Ratio
Tes (Ratio: Money sharing loop cards): https://www.tes.com/en-au/teaching-resource/ratio-sharing-money-loop-cards-11795903
Tes (Simplifying ratio loop cards): https://www.tes.com/en-au/teaching-resource/simplifying-ratio-loop-cards-11926074
Tes (KS3 Ratio and Proportion): https://www.tes.com/en-au/teaching-resource/ks3-ratio-and-proportion-mep-year-8-unit-7-6051312
Tes (Exchange rates using proportion worksheet): https://www.tes.com/en-au/teaching-resource/exchange-rates-using-proportion-worksheet-6343853
Tes (Proportion practice questions + solutions): https://www.tes.com/en-au/teaching-resource/proportion-practice-questions-solutions-6330181
Direct and inverse proportion: https://www.pearsonschoolsandfecolleges.co.uk/AssetsLibrary/SECTORS/Secondary/SUBJECT/Target%20_Intervention/PDF/Unit-6-Direct-and-Inverse-Proportion.pdf
Tes (Direct/inverse proportion): https://www.tes.com/en-au/teaching-resource/direct-inverse-proportion-6386769
Mathsteacher (converting rates from one unit to another): https://www.mathsteacher.com.au/year8/ch14_rates/02_conv/unit.htm
Khan Academy (ratio problems): https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-rates/e/rate_problems_0.5