**Answer:** (0! + 0! + 0! + 0! + 0!)! = 120.

Since 0! = 1 we have (1 + 1 + 1 + 1 + 1)! = 5! = 1 x 2 x 3 x 4 x 5 = 120, as required.

Where ! means factorial, and where factorial means you take all numbers from 1 to your number and multiply them together.

For example:

0! = 1 (by convention)

1! = 1

2! = 1 x 2 = 2

3! = 1 x 2 x 3 = 6

4! = 1 x 2 x 3 x 4 = 24

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10!= 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 = 3,628,800.