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The answer is 1 in 2313441.
If this precisely matches your calculation, congratulations: you have passed a rudimentary test of your grade 11 math skills.
In order to generate this figure, you could always use the counter below, but that would be a rather inefficient way to handle the problem. The simpler way is to recognize that you have 39 choices for each of 4 numbers, so the total number of combinations is 39*39*39*39, or 39^4. This is the simplest type of random probability calculation, because you can pick a number more than once (so you don't need to multiply by successively smaller numbers) and the order is fixed (so you don't need to divide by all the possible orders). If the order was not fixed and you could not pick the same number more than once, then you could do 39C4, so your odds would be 1 in 82251.
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