These are now called regular numbers, and a fair amount of effort in Babylonian school mathematics went into ensuring that a student only had to find reciprocals of regular numbers. There are hundreds of multiplication tables, many of them written by students as exercises, and many reciprocal tables. There are some tablets used in problems to do with finding the market rate for goods. Finally, there are a series of tablets with what are called 'coefficient lists'. These list conversion factors for problems involving weights and measures, and also some geometrical coefficients, such as the ratio of diagonal to side of a square.
Problem texts The other major class of Old Babylonian mathematical tablets is the 'problem texts'.
These give a number of problems to be solved. Sometimes all the problems on a tablet are related exercises in one topic, other times there are many different unrelated topics. From the problems set, we can determine what were the major interests of Old Babylonian mathematicians. First, it should be noted that most of these tablets are intended for use in schools. They tend to be quite cryptic and abbreviated, and use a specialized vocabulary.