TASK DEFINITION: The task is to generate the correct answer for a given math problem.
PROBLEM: Problem: of the seven - digit positive integers that have no digits equal to zero , how many have two digits that are equal to each other and the remaining digit different from the other two ?

SOLUTION: 152409600

PROBLEM: Problem: calculate the sum of first 60 natural numbers .

SOLUTION: 1830

PROBLEM: Problem: solve for x and check : - 3 x = 12

SOLUTION:
- 4