The use of slide rules continued to grow through the NUMBER@1 and NUMBER@2 even as digital computing devices were being gradually introduced ; but around NUMBER@3 the electronic scientific calculator made it largely obsolete and most suppliers exited the business .

The use of slide rules continued to grow through the NUMBER@1 and NUMBER@2 even as digital computing devices were gradually introduced ; but around NUMBER@3 the electronic scientific calculator made the slide rule largely obsolete and most suppliers exited the business .
