Why does plus change to minus in 1st-year junior high math 'transposition'? Equations seen through a balance scale

This page is about 'transposition' (iko), which is taught in the first year of junior high school mathematics.Transposition ...
The Chronicle of Higher Education

Casting Out Nines: Math Monday: Columnar transposition ciphers and permutations, oh my

I hope you enjoyed Ed’s guest posts on NP-complete problems on TV the last couple of Mondays. It’s always great to hear from others on math that they are thinking about. This week it’s me again, and ...
TES

Algebra 1: Transposition of formulae: One Step Equations

Algebra 1: Transposition of formulae: One Step Equations. This can be used as either an introductory lesson or form part of revision and could even be used to form the basis of a lesson observation.
TES

Algebra 1: Transposition of formulae: One Step Equations

Algebra 1: Transposition of formulae: One Step Equations. This can be used as either an introductory lesson or form part of revision and could even be used to form the basis of a lesson observation.