Answer:
The answer is 7 because if we write 7 - 8 = -1, then we could see that the answer would be -1 since 7 is 1 value lower than 8, and 8 - 8 = 0, so if 7 is lower than 8 by 1, then you would go one value lower from 0, which is -1. You can also figure this out by looking at a number line and starting from 7 and then going backwards 8 times and whatever number you land on after going back 8 times is your answer.