Here, we have to estimate the given numbers to the nearest 100.
Consider the tens digit and ones digit.
If the hundreds digit is greater than 5, then the tens digit and ones digit will be replaced with 0 and the hundreds digit will be increased by 1.
If the hundreds digit is less than 5, then the tens digit and ones digit will be replaced with 0 and the hundreds digit will remain the same.
So,
267 can be estimated to 300,
442 can be estimated to 400,
699 can be estimated to 700 and
578 can be estimated to 600.