Since we are forming 5-digit numbers, the first digit cannot be 0. Therefore, we have 7 choices for the first digit. After choosing the first digit, we have 7 remaining digits to choose from for the second digit, 6 remaining digits for the third digit, 5 remaining digits for the fourth digit, and 4 remaining digits for the fifth digit. So, the total number of 5-digit numbers that can be formed is 7 * 7 * 6 * 5 * 4 = 5,040. To find the sum of these numbers, we can use the formula for the sum of an arithmetic series: S = (n/2)(a + l), where S is the sum, n is the number of terms, a is the first term, and l is the last term. In this case, the first term is 1,2345 (the smallest 5-digit number that can be formed using the given digits) and the last term is 7,6543 (the largest 5-digit number that can be formed using the given digits). Using the formula, we can calculate the sum as follows: S = (5040/2)(12345 + 76543) S = 2520 * 88888 S = 224,217,600 Therefore, the sum of all numbers that can be formed using the digits 0, 1, 2, 3, 4, 5, 6, 7 is 224,217,600. ...