倍
Meaning
倍 is a measure word showing how many times larger or smaller one quantity is than another. Unlike most measure words, 倍 is not followed by a noun.
Basic structure
A + 是 + B + 的 + Number + 倍
Examples
二的五倍是十
我的工资是每月五千块，他的工资是我的两倍
我记得昨天才三块五一斤，今天的价格是昨天的两倍
Careful: 是……的……倍 vs. 增加了……倍
今年的收入增加了一倍
是……的两倍 = twice, 是……的三倍 = three times — the number says it plainly.
But 增加了 / 多了 counts differently: 增加了一倍 = doubled (up 100%), 增加了两倍 = tripled.
倍 vs. 百分之
工资是以前的三倍
增长了百分之二十
倍 → how many times.
百分之 → what percentage.
Remember:
倍 = times.
A 是 B 的 + Number + 倍.
增加了一倍 = doubled — this is where learners slip most often.