Grandad is 11 equal units. Ed is 2⁄11 of grandad, so 2 of those units = 12 years.

Grandad66666666666Ed6612

Plain numbers are given; italic underlined numbers are worked out.

  1. Ed = 2 units → 12
  2. 1 unit → 12 ÷ 2 = 6
  3. Grandad = 11 units → 11 × 6 = 66

His grandad is 66 years old.

Check: 2⁄11 of 66 = 12 = Ed. ✓