In #MathsToday I sketched this str line through 12,0 and 0,12 and asked for the coords of other points on the line. The Y11 student tried x=6 and thought y might be 8, or 7, or, eventually, 6. After agreeing 12,0 0,12 6,6 3,9 7,5 and 1,11 it took a while to spot x+y=12. The student 'knows' y=mx+c.
24 days ago