Different age but similar messaging - Currently developing Yr 3/4 group, +4 years above peers. Choosing lessons to enrich thinking not just upwards. Using below as my touchstone. Started figurative numbers relationships as they'd know 'the tricks' from tutoring, so focus on patterns and reasoning

If you're still looking for ideas, many ideas within variety of Figure It Out lessons but particularly within the Proportional Reasoning books. In NZ level 3 relates to learning generally in yr 5 and 6, Level 4 Yr 7 & 8 etc.
newzealandcurriculum.tahurangi.education.govt.nz/figure-it-ou...