How to pull one document amoung multiple similar documents in MongoDB

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C#

MongoDB

Let the document in mongoDb be as followes

Marks:[10,10,11,12]

from this i would like to remove only one 10
i.e., result should be

Marks:[10,11,12]

when i tried update.pull with query as
var query = new QueryDocument {{"Marks",10}};
both 10's are been pulled out of the document.

Thanks in advance :)