calculate : 通常指要求细致精确和复杂的计算，以解决疑难问题，多用于自然科学、生产部门或要求专门计算的场合。
- The cost of the damage caused by the recent storms has been calculated as/at over £5 million.
- The new tax system would be calculated on the value of property owned by an individual.
- At some stage we need to calculate when the project will be finished.
- He's calculated that it would take him two years to save up enough for a car.
count : 指逐一计算而得出总数。
- Let's count out loud (= speak the words) from one to ten.
- The teachers counted the students as they got on to the bus.
- Count your money carefully to make sure it's all there.
- We need to count who's here, so we can make sure that no one's missing.
- There'll be eight for dinner, counting (= including) ourselves.
- We're still waiting for the votes to be counted (up).
compute : 一般指已有数据的，较简单但数字长的数学运算。
- Compute the ratio of the object's height to its weight.
reckon : 通常指较简单的数学计算，也可指心算。
- Angela quickly reckoned the amount on her fingers.
- The inflation rate is now reckoned to be 10 percent.
- The star's surface temperature is reckoned to be minus 75 degrees Celsius.