calculate: is usually preferred in reference to highly intricate and precise processes that produce a result not readily proven by physical confirmation: ~d when the comet would next appear. physical confirmation实际(物理)验证
compute: is the term for reaching an exact result by simpler though often lengthy arithmatic processes: ~d the interest at a monthly rate. 写成arithmatic或arithmetic都正确arithmatics is the part of mathematics that involves basic calculations such as adding or multiplying numbers算术是数学的一部分，仅涉及加减乘除等基本运算
estimate: applies chiefly to the forecasting of costs or trends and suggests a seeking of usable but tentative and approximate results: the mechanic ~d the cost of repairs.
reckon: usually suggests the simpler arithmatic processes or the use of methods such as can be carried out in one's head: ~ed the number of yards of fabric needed.
/1 
