理解加法和减法是互为逆运算；

Understand that addition and subtraction are inverse.

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

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