Back-of-the-cigarette-packet - Tradução em português

Reaching his fourth decade brings rich rewards for Prince William, and that's not just his grandmother's gift of the Order of the Thistle, the highest honour in Scotland, whose insignia he proudly displayed for the first time during Saturday's trooping the colour.
Rather, he is now entitled to inherit a substantial sum from the estate of his mother, the late Diana, Princess of Wales. Some back-of-the-cigarette-packet calculations put it at around £10m.