What does the smallest numbers mean on this speedometer? (picture included)?

I have a 1979 Honda CB125S that has a speedometer with scale for MPH and KMH but there's a smallest number that are from 1 to 5. Would this be the gear shift numbers?What does the smallest numbers mean on this speedometer picture included

Ding ding ding! We have a winner. Yea, that is what the numbers are for, genius.

You have a 5 speed manual gear stickshift
it shows the maximum safe speed for each gear