The phrase is said during the _mamemaki_ performed as part of _Setsubun_.
It is often recited _rhythmically_
> []{}[]{}[]{}[]{}[]{}[]{}[]{}[]{}[]{}[]{}[]{}[]{}
Just writing just looks/reads very ordinary, so here the small is added to convey the (rhythmical) sound of the children singing/reciting the phrase.
(Rhythm can also change the pronunciation of the numbers when counting, for example during hide-and-seek.)