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 methods that can be carried out in one's head: ~ the number of yards of fabric needed.  


calculate计算: 高度复杂、精确的计算操作, 结果不易验证, compute也是计算: 较简单但更冗长的算术运算, estimate估计: 指大略地尝试性地预测成本趋势等, reckon心算: 可以在大脑中进行的简单算术


记忆方法: 1) CCRE想成ChangChang RE: 常常算，再次(RE)算<==提高计算能力         "算"的本义是1、计数，如笔算心算计算算账算盘 引申为2、承认有效，如算数算话 3、推测计划，如算计算命推算打算谋算机关算尽人算不如天算，又如我算着他明天准来表示推测。此字起源不详。    "计"是会意字，从言从十，本义是1、算数，如计算合计计入预计 引申为2、用于算数测量的仪表，如温度计静电计  3、谋划打算，如"父母之爱子，则为之计深远"，"计者，所以定事也"，国计民生，如"校之以计，而索其情"出自《孙子兵法》第一篇《始计》，是其点睛之笔。

         2）练习一下

         3) 计算的意思是用数学方法确定mean to determine something mathematically.CCRE想成ChangChang RE: 常常算，再次(RE)算<==人人提高计算能力