Cyrillic i writes the same vowel and takes the numeral ten, against the twenty that Glagolitic gives it. Ten is the value of Greek iota, and the Cyrillic figure is inherited from it directly. The Glagolitic figure comes from counting its own letters, and the two systems are now a full decimal step apart, which is the clearest divergence so far and the reason a number copied between the scripts without conversion is so easy to misread.
Both alphabets carry two i letters, and both inherit the redundancy from Greek rather than from anything in Slavonic. The parallel is a real point of contact between the scripts: whatever the relationship between them, both were arranged by someone working from the Greek alphabet as it was read in the ninth century, and both carried across a distinction that their own language did not require.
Where they differ is in what happened afterwards. The Cyrillic pair survived into the modern orthographies of several Slavic languages and was reduced by spelling reform at different dates in different countries, so the history of the pair after the medieval period is a history of committees and decrees. The Glagolitic pair simply went out of use with the script, except in the Croatian liturgical tradition, where it lasted for centuries longer.