Shoe size "Footwear - Sizing - Vocabulary and terminology"; currently in development are companion standards ISO/TS 19409 "Footwear - Sizing - Measurement of last dimensions" and ISO/TS 19410 "Footwear - Sizing - Inshoe measurement". The adult shoe sizes are calculated from typical last length, which is converted from foot length in mm by adding an allowance of two shoe sizes: where formula_13 is foot length in mm. Direct conversion between adult UK, European and Mondopoint shoe size systems is derived as follows: Exact foot lengths may contain repeating decimals because the formulas include division by 3; in practice, approximate interval steps of
ISO 10303 and different speed in the development processes, the splitting into several APs was needed. But this splitting made it difficult to ensure that APs are interoperable in overlapping areas. Main areas of harmonization are: For complex areas it is clear that more than one APs are needed to cover all major aspects: STEP programs ISO 10303 ISO 10303 is an ISO standard for the computer-interpretable representation and exchange of product manufacturing information. Its official title is: "Automation systems and integration — Product data representation and exchange". It is known informally as "STEP", which stands for "Standard for the Exchange of