Each digit of a five-digit number is one more than the previous one, and the sum

Each digit of a five-digit number is one more than the previous one, and the sum of its digits is 30. What is this number?

Suppose that the required five-digit number is written in digits a, b, c, d, e.

Since each digit of a five-digit number is one more than the previous one, we have:

b = a + 1, c = b + 1 = a +2, d = c + 1 = a + 3, e = d + 1 = a + 4.

By the statement of the problem, it is known that the sum of the digits of this five-digit number is 30.

Therefore, we can make the equation:

a + b + c + d + e = 30,

a + (a + 1) + (a + 2) + (a + 3) + (a + 4) = 30,

5 * a + 10 = 30,

5 * a = 20,

a = 4.

Thus, we got that the required five-digit number is 45678.

Answer: the required five-digit number is 45678.