Cyrillic nash writes the same consonant from the same position and takes the numeral fifty, the value of Greek nu. Glagolitic counts seventy. The names differ only in the ending, and both continue the Slavonic word for our.
At this letter the two alphabets are running twenty apart, and the offset will change again shortly, because the letters that follow include signs that one system numbers and the other does not. Anyone converting a numeral between the scripts has to work letter by letter through the order rather than apply a constant.
The two nash letters are also a good place to observe how the alphabets were taught. The order was learned by reciting the names, not by reciting the sounds, and the mnemonic value of names that are ordinary words is obvious: a learner who forgets a shape can still recover the sequence. That the same names served both scripts means the teaching tradition was continuous across the change from one alphabet to the other, whichever direction that change ran in. The names are, in that sense, older evidence than either set of letterforms, and they are what the two scripts most clearly hold in common.
They are also unevenly informative. The names at this end of the alphabet are ordinary Slavonic words whose sense anyone can read, while the names further down are opaque, and no etymology for them has been established. The atlas records that gap as an open question rather than filling it with a guess.