Final answer:
To solve the problem 30 (155) using subtraction, subtract each digit from right to left, borrowing if necessary. The answer is -2.
Step-by-step explanation:
To solve the problem 30 (155) using subtraction, you need to subtract 155 from 30. Subtract each digit from right to left, starting with the ones place. If the digit being subtracted is higher than the digit at that place, borrow from the next higher place value. In this case, it is not possible to subtract 5 from 0, so you will need to borrow from the tens place. Subtracting 5 from 10, you get 5. Then subtract 5 from 3, which gives you -2. Therefore, the answer is -2.
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