The conversion rate of millimetres to centimetres is 10 = 1 (Meaning 10 millimetres will equal one centimetre).
Knowing this, we can convert the centimetres to millimetres by multiplying by 10.
30 x 10 = 300
So a walking stick is 300 millimetres long.
To find the difference, we need to subtract the larger number from the smaller one.
300 - 10 = 290
Therefore the answer is 290mm.
Hope this helps! :)
