Narrated 'Imran bin Husain (RA):

A man came to the Prophet (ﷺ) and said, "My son's son (grandson) has died, so what do I receive from his estate (inheritance)?" He replied, "You receive a sixth;" then when he turned away he called him and said, "You receive another sixth;" and when he turned away he called him and said, "The other sixth is an allowance (beyond what is due)." [Reported by Ahmad and al-Arba'a. at-Tirmidhi graded it Sahih (authentic)].

وَعَنْ عِمْرَانَ بْنِ حُصَينٍ قَالَ : جَاءَ رَجُلٌ إِلَى اَلنَّبِيِّ ‏- صلى الله عليه وسلم ‏-فَقَالَ : { إِنَّ اِبْنَ اِبْنِي مَاتَ , فَمَا لِي مِنْ مِيرَاثِهِ ? فَقَالَ : " لَكَ اَلسُّدُسُ " فَلَمَّا وَلَّى دَعَاهُ، فَقَالَ: "لَكَ سُدُسٌ آخَرُ" فَلَمَّا وَلَّى دَعَاهُ.‏ فَقَالَ : " إِنَّ اَلسُّدُسَ اَلْآخَرَ طُعْمَةٌ } رَوَاهُ أَحْمَدُ وَالْأَرْبَعَةُ , وَصَحَّحَهُ اَلتِّرْمِذِيُّ [1]‏