Don't look at the threesome, just for neatness and readability. Think about it, if there is no separation in the middle, it will be too much trouble to read.

The random number table method is to randomly select a row and a column in the random number table as the starting point. For example, 7, 3, starting from the third column of the seventh row. What is needed is three digits, so start with this number and read with three digits. If these three figures meet the requirements, take them out and read them. If this three-digit number does not meet the requirements, then leave it out and read the next three-digit number. Until the data you are looking for meets the meaning of the question.