The Roman numeral XLVIII stands for the Arabic numeral 48. The individual numerals "X," "L," "V" and "I" stand for the Arabic numerals 10, 50, 5 and 1, respectively.
When using Roman numerals, placing a lower numeral prior to a larger one indicates that a person should subtract the smaller amount from the larger. Therefore, to create the number 40, Roman numerals place "X" before "L." By contrast, when smaller numerals come after larger ones, the reader should add their values to the preceding value. Thus, the "V" adds 5 to 40, and the "III" at the end of the numeral adds another three units to the preceding value, yielding an ultimate value of 48.