Final answer:
To subtract 68.57 from 667.8, subtract the digits in each place value starting from the right. To check the answer, subtract the result from the number on the left and confirm if it matches the initial subtraction.
Step-by-step explanation:
To subtract and check the following numbers, 667.8 - 68.57, you simply subtract the digits in each place value, starting from the right. So, 7 - 7 equals 0, 8 - 5 equals 3, 7 - 6 equals 1, and 6 - 8 equals -2. Since we have a negative result, we would subtract it from the number on the left to check the answer. So, 667.8 - (-2) equals 669.8, which confirms that our subtraction is correct.