Qt/C++ composition, multiplication and reading of numbers in line

The first task was to create a class that takes on the entrance, and keeps the numbers (full and with a floating back) in the form of lines, and which will allow to do over the similar numbers the process of composition and reading. After it was performed, the customer contacted me again, so that I added the possibility of multiplying such numbers. All projects have been successfully implemented.

Windows Platform, Qt 5.15, MinGW 64 8.1