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Find Missing Number in Python Sequence 1 to N

Find the missing number from a list containing numbers 1 to N using the arithmetic sum formula.

missing-number arithmetic sum
Python 
def find_missing_number(nums, n):
    expected_sum = n * (n + 1) // 2
    actual_sum = sum(nums)
    return expected_sum - actual_sum


if __name__ == "__main__":
    n = 10
    numbers = [1, 2, 3, 4, 5, 6, 7, 9, 10]
    missing = find_missing_number(numbers, n)
    print(f"The missing number is: {missing}")
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