Disintegrating: it’s a new maths thing (12)

I believe the answer is:

whatsitsname

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'thing' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'disintegrating it's a new maths' is the wordplay.
'disintegrating' indicates anagramming the letters (I've seen 'disintegrated' mean this).
'its'+'a'+'new'+'maths'='itsanewmaths'
'itsanewmaths' is an anagram of 'WHATSITSNAME'.

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I've seen this clue in The Times.

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