There is no direct fomula
But you can do it indirectly:

Let a1 be 100
in cell a2,type the formula rand()*10
in cell a3,type rand()*100-a2
in cell a4,type rand()*100-sum(a2:a3)
..
..
..
in cell a9,rand()*100-sum(a2:a9)
in cell a10,100-sum(a2:a9)

Hope you got the idea.The only disadvantage is there may be a negative
value in cell a10.
To avoid this and to get better results, use the SOLVER option(found in
add-ins menu)

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