Probably one of the most widely used MSI arithmetic circuits is the 74283 4-bit adder. Several of them could be wired in series to perform 8-bit, 16 bit or even 32-bit operations. This is the internal circuitry of a 74HC283 from Philips: ![enter image description here][1] which shows it is clearly of MSI complexity. [1]: https://i.sstatic.net/CSwDh.jpg