Estimate each product. Tell whether your estimate is an overestimate or underestimate.
1) 2x3991 is about (Round to the thousands) ( over/underestimate)
2)80x127 is about (Use compatible numbers) ( over/underestimate)
1) 2x3991 is about 7982. This is an exact calculation and there is no overestimate or underestimate.
2) 80x127 can be estimated by using compatible numbers. 80 can be rounded to 100 and 127 can be rounded to 125. Therefore, 100x125 is about 12,500. This is an underestimate as the actual product is 10,160.