Four-digit numbers

Find four-digit numbers where all the digits are different. For numbers, the sum of the third and fourth digits is twice the sum of the first two digits, and the sum of the first and fourth digits is equal to the sum of the second and third digits. The digit 0 must not be in the first position of the number. How many are there?

Correct answer:

n =  10

Step-by-step explanation:

n1=1548 n2=2031 n3=2457 n4=3153 n5=3579 n6=4062 n7=4275 n8=5184 n9=5397 n10=6093  n=10

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