1. is 100 rounds to 100 and 99 rounds to 100.

2. 100 + 99 = 199 which est to be 200.

3. 100 - 99 = 1 Which est.to be 0 zero.

To answer your questions, I will break them down step by step:

1. Is 100 rounded to 100, and 99 rounded to 100?
To determine if a number is rounded to another number, we need to consider the rules for rounding. When a number is exactly halfway between two consecutive whole numbers, we round up to the nearest whole number. In this case, 100 and 99 are both whole numbers, so we need to check if they are exactly halfway between another pair of whole numbers.

- For 100, there are no whole numbers between 100 and the next whole number, so it remains as 100.
- For 99, it is exactly halfway between 90 and 100. Since it is closer to 100, we round up to 100.

Therefore, 100 is rounded to 100 and 99 is also rounded to 100.

2. You mentioned that 100 + 99 equals 199, but you estimated it to be 200.
Adding up 100 and 99, we get 199. However, if we estimate the sum, we can round each number to the nearest ten. Rounding 100 to 100 and 99 to 100, we can then add these rounded numbers together: 100 + 100 = 200. So while the exact sum is 199, the estimated sum when rounding to the nearest ten is 200.

3. You mentioned that 100 - 99 equals 1, but you estimated it to be 0 (zero).
Subtracting 99 from 100, we indeed get 1 as the exact difference. However, if we estimate the difference, we can round each number to the nearest ten. Rounding 100 to 100 and 99 to 100, we then subtract the rounded numbers: 100 - 100 = 0. So while the exact difference is 1, the estimated difference when rounding to the nearest ten is 0 (zero).