Ben = 1 unit, Louis = 6 units. Altogether 7 units = 42 cards. Louis has 5 units more than Ben.

Ben1Louis11111142

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

  1. 7 units → 42
  2. 1 unit → 42 ÷ 7 = 6 (Ben)
  3. Louis − Ben = 5 units → 5 × 6 = 30

Louis has 30 more cards than Ben.

Check: Ben 6 + Louis 36 = 42, and 36 − 6 = 30. ✓