When decimal numbers are within the range of 0 to 9, their binary and BCD representations are identical, requiring only four bits (0000 to 1001).

Conversion of binary to decimal numbers is often needed in firmware. And it’s done easily enough if multiplication and division by ten are acceptable.

LEGO binary to decimal conversion [Carl] is doing a few experiments to see if it’s possible to build a calculating machine out of LEGO. He managed to convert four bits of binary into decimal.