该服务是一个简单的数学计算服务，提供了加法和减法运算。

This service is a simple math calculation service, providing addition and subtraction operations.

youdao

世界上第一台计算机EMNIAC每秒可进行A次加、减法运算。

The world's first computer per second EMNIAC can add, subtract a times.

youdao

对于加减法运算所需循环的平均数是2，而旧型号机却需12—15。

For adds and subtracts, the average number of cycles required is two, versus about 12 to 15 for the previous type.

youdao

Same sort of subtraction problem, what do we have for the ionization energy of the 2 s electron?

进行类似的减法运算,得到的，2，s，电子的电离能应该是多大呢？

麻省理工公开课 - 化学原理课程节选