Malcolm = 11 units, Liam = 9 units. Malcolm is 2 units taller, and that is 34 cm.

LiamMalcolm2 units = 34 cm

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

  1. Difference → 11 units − 9 units = 2 units → 34 cm
  2. 1 unit → 34 ÷ 2 = 17 cm
  3. Liam → 9 units = 9 × 17 = 153 cm

Liam is 153 cm tall.

Check: Malcolm 11 × 17 = 187; 187 − 153 = 34. ✓