Convert roman numerals CCXLII in Hindu-Arabic numerals?

CCXLII:

Value of C = 100, Value of X = 10, value of L = 50, value of I = 1

According to the rules of roman numerals, when a symbol of a smaller value appears after a symbol of greater value, its value is added to the greater number whereas when a symbol of a smaller value appears before a greater value symbol, it is subtracted from the greater value.

$\therefore$CCXLII= C + C + (L-X) + I + I = 100 + 100 + 50 - 10 + 1 + 1 = 242.