"100" in Engpsh is written as "one hundred."
The number system we use in Engpsh is based on the Hindu-Arabic numeral system, which has its origins in ancient India. It was later adopted and spread throughout the Arabic-speaking world, and eventually made its way to Europe during the Middle Ages.
Examples:
"I have one hundred dollars." (我有100美元。)
"He scored one hundred on the test." (他在考试中得了100分。)
"One hundred is a round number." (100是一个圆整数。)