Open Up Resources. Grade 6 Math. 2nd Edition. 3 workbooks:
Unit 6 - Student Workbook (2018)
Unit 7 - Rational Numbers (2019)
Unit 8 - Student Workbook (2018)
No markings within, except 3 pages in Unit 8. They have been erased and pictured - 2 are worksheets, 1 is on a "notes" page. You can tell that they were written on and then erased, but they should copy clean.