John Gill Commentary Numbers 11:19

"Ye shall not eat one day, nor two days, nor five days, neither ten days, nor twenty days," — Numbers 11:19 (ASV)

You shall not eat one day
Only, as in (Exodus 16:12) ;

nor two days, nor five days, neither ten days, nor twenty days ;
but even thirty days, a whole month, as in (Numbers 11:20) .