Sure, no problem.
The LEN formula works out the total number of characters in a cell;
The RIGHT formula extracts characters from another cell starting from the last character in the cell i.e. the rightmost character. The number of characters to be extracted is based on the number you specify in the formula e.g. if cell A2 has alphanumeric data for instance and we wanted to extract only the numbers from the data within it which has CNB1579, we could write the formula =RIGHT(A2,4) in another cell so that the last 4 characters in the rightmost part of the string i.e. 1579 of A2 will be extracted. If the formula was =RIGHT(A2,3), we would extract 579 and if the formula was =RIGHT(A2,2), we would extract 79 etc.
If we use B2 as an example from your dataset, the data displayed is [Space]829. The space is counted as a character so the LEN formula calculates that B2 has 4 characters. As you want to extract everything except the space in the RIGHT formula we deduct 1 from the full number of characters the cell contains so the space at the start of the cell is not extracted hence the expression in the formula LEN(B2)-1. In this instance, this returns the number 3.
Essentially, the formula =RIGHT(B2,LEN(B2)-1) is the same as saying =RIGHT(B2,3). However, we use the LEN formula in this instance instead of just writing 3 to make the formula dynamic because you have various numbers in your data set of varying lengths to which we apply this formula. As such, if we were to write =RIGHT(B19,3) to extract the 1279 from cell B19 in your dataset, we would only get back 279 instead of the full number which would be incorrect. As such, the use of LEN in conjunction with RIGHT lets Excel consider the full character length of each cell when extracting the correct number of characters. =RIGHT(B19,LEN(B19)-1) in this instance is understood in the context of B19 as =RIGHT(B19,4) i.e. the full length of the cell being 5 minus 1 for the space.
I hope this helps.
Let me know if you need further information.
With kind regards,
Judith