I asked Ibn 'Abbas how old was he when death overtook the Messenger of Allah ﷺ. He said: I little know that such a thing is not known to a man like you who belong to his people. He said: I asked people about it but they differed with me, and I liked to know your opinion about it. He said: Do you know counting? He said: Yes. He then said: Bear this in mind very well that he was commissioned (as a Prophet) at the age of forty, and he stayed in Mecca for fifteen years; sometime in peace and sometime in dread, and (lived) for ten years after his migration to Medina. (Using translation from Muslim 2353a)   

سَأَلْتُ ابْنَ عَبَّاسٍ كَمْ أَتَى لِرَسُولِ اللهِ ﷺ يَوْمَ مَاتَ؟ قَالَ مَا كُنْتُ أُرَى مِثْلَكَ فِي قَوْمِهِ يَخْفَى عَلَيْكَ ذَلِكَ قَالَ قُلْتُ إِنِّي قَدْ سَأَلْتُفَاخْتُلِفَ عَلَيَّ فَأَحْبَبْتُ أَنْ أَعْلَمَ قَوْلَكَ فِيهِ قَالَ أَتَحْسِبُ؟ قُلْتُ نَعَمْ قَالَ أَمْسِكْ أَرْبَعِينَ بُعِثَ لَهَا وَخَمْسَ عَشْرَةَ أَقَامَ بِمَكَّةَ يَأْمَنُ وَيَخَافُ وَعَشْرًا مُهَاجِرًا بِالْمَدِينَةِ  

[Machine] I asked Ibn Abbas how many times did he visit the Messenger of Allah ﷺ on the day he died? He said, "I have never seen anyone like you hiding that information from you." I said, "Indeed, I have asked, but I received conflicting answers, so I wanted to know your opinion." He said, "Do you think so?" I said, "Yes." He said, "Take forty ripe dates. Fourteen of them are in Makkah, where he is safe and secure, and ten of them are in Madinah."  

قُلْتُ لِابْنِ عَبَّاسٍ كَمْ أَتَى لِرَسُولِ اللهِ ﷺ يَوْمَ مَاتَ؟ قَالَ مَا كُنْتُ أَرَى مِثْلَكَ مِنْ قَوْمٍ يَخْفَى عَلَيْكَ ذَلكَ قَالَ قُلْتُ إِنِّي قَدْ سَأَلْتُ فَاخْتَلَفَ عَلَيَّ فَأَحْبَبْتُ أَنْ أَعْلَمَ قَوْلَكَ فِيهِ قَالَ أَتَحْسِبُ؟ قُلْتُ نَعَمْ قَالَ «خُذْ أَرْبَعِينَ بُعِثَ لَهَا وَخَمْسَ عَشْرَةَ مُقَامُهُ بِمَكَّةَ يَأْمَنُ وَيَخَافُ وَعَشْرًا مُهَاجَرُهُ بِالْمَدِينَةِ»