calculate，compute，estimate
calculate通常指用数学方法进行比较复杂，难度较大的精确计算。如：You can't expect a schoolboy to calculate distances in astronomy.
compute常指比较简单的运算。如：It was computed that two thirds of the students in the class passed the examination.
estimate估计，常指对数量、成本等事先进行判断或估计。如：Some farmers asked the weatherman to estimate next year's rainfall.
