summary of chapter 2 in Data Structure and Algorithm Analysis in C

Question

When summarized the chapter 2, the author mentioned that

"Specifically, a 200-digit number is raised to a large power (usually another 200-digit number), with only the low 200 or so digits retained after each multiplication."

Q :What is this mean? PS:My English is a little bad.

Answer 1

如果将200替换为3，这将意味着类似于计算123 ^ 456，但仅保留低3位数字（一个，几十个和几百个位），在数学上等同于（123 ^ 456）％1000。