The phrase guestimate is a combination of the words guess and estimate. Guesstimates are estimates based on the scant information provided. An estimate is a guess based on knowledge rather than an exact response. Overall, the term stands for an approximation based on accessible facts and a guess based on current knowledge. These questions are simple to answer if you break them down into four parts. The first step is to define any ambiguous words in the query. The second stage is to divide big numbers into smaller, more manageable chunks. The third step is to estimate each element based on previous experience. The final step is to bring all of the pieces together and present your findings.