倍數英文是甚麼？

倍數小的時候有專有名詞或者形容詞。如2倍 double﹐3倍 triple﹐4倍Quadruple.....倍數大的會用times。如20倍 = 20 times﹐30倍 = 30 times.
A multiple of 20 是指20的倍數﹐并不是20倍。數學上用得比較多。例如 Write down all multiples of 3 greater than 10 but smaller than 20.

20倍，30倍、45倍
20 times, 30 times, 45 times

multiple of 20s...
嚴格而言寫法是：乘以20的倍數

multiple
e.g. multiple of 20, multiple of 30............