$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}} = {\mathtt{19}}$$

I'm sure the poster intended factorial 10 there.

9 + 10! = 9 + 10x9x8x7x6x5x4x3x2x1 = ......  (answer)

That final computation is left as an exercise for the student. 

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whats 9+10.... 21!!!!