When estimating 4,629 + 6,331 do I round up the thousands to 5,000 + 6,000 or do i round to the hundreds, 4,600 + 6,300? Thank you in advance.

If it simply asked to estimate, then it would be a poorly-worded question.

Usually it will say something like
"Estimate to the nearest thousand", in that case I would say 5000+6000

On the other hand, if "... to the nearest hundred"
then 4600+6300

Check the wording, you will have to decide.

It just says, "Estimate each sum or difference." ~ Thank you for your help.

When estimating the sum of 4,629 and 6,331, you have a couple of options for rounding. The answer will vary depending on the level of accuracy you want in your estimation.

If you want a rough estimate while rounding to the nearest thousand, you can round 4,629 to 5,000 and 6,331 to 6,000. Then, adding these rounded numbers together, you would estimate the answer as 5,000 + 6,000 = 11,000.

On the other hand, if you prefer a more precise estimation while rounding to the nearest hundred, you would round 4,629 to 4,600 and 6,331 to 6,300. Then, adding these rounded numbers together, you would estimate the answer as 4,600 + 6,300 = 10,900.

The choice between rounding to the nearest thousand or nearest hundred depends on your desired level of accuracy. If you are seeking a quick approximation, rounding to the nearest thousand is sufficient. If you want a slightly more precise estimate, rounding to the nearest hundred is a better option.