A logarithm is a number that stands for another number in a special maths system. The useful trick is this: if you want to multiply two hard numbers, you can add their logarithms instead, which is much easier.

A logarithmlogarithm is就是 a number一個數字 that stands for代表 another number另一個數字 in a special maths system在一種特殊的數學系統裡。The useful trick is this有用的訣竅是: if you want to如果你想 multiply two hard numbers把兩個很難算的數字相乘, you can add their logarithms instead可以改成把它們的logarithm相加, which is much easier這樣簡單多了

Before cheap calculators, people used printed logarithm tables for this. At school it is usually written log, and sometimes ln for a special kind.

Before cheap calculators在便宜的計算機出現之前, people人們 used printed logarithm tables用印出來的logarithm表 for this來做這件事。At school在學校裡 it is usually written通常寫成 loglog, and sometimes有時候寫成 lnln for a special kind某種特別的情況

It is a classroom and science word, not an everyday one.

It它 is a classroom and science word是課堂和科學用語, not an everyday one不是日常會用的字

A “logarithmic scale” (earthquakes, sound, some graphs) uses this idea: each step is a jump in size, not a small equal step. The word is long, but the job of the word is only to count how far a number sits from a starting value when you grow it by the same ratio again and again.

A “logarithmic scale”logarithmic scale（對數尺度） (earthquakes, sound, some graphs)（地震、聲音、某些圖表） uses this idea就是用這個概念: each step每一步 is a jump in size是等級的跳躍, not a small equal step不是一小段固定不變的增加。The word這個字 is long很長, but但 the job of the word它的作用 is only to count只是計算 how far a number sits from a starting value一個數字離起始值有多遠 when you grow it by the same ratio again and again當你用同樣的倍率一次又一次成長時