The Prophet ﷺ prayed two rakʿat of Zuhr prayer (instead of four) and he was told that he had prayed two rakʿat only. Then he prayed two more rakʿat and finished them with the Taslim followed by two prostrations.  

صَلَّى النَّبِيُّ ﷺ الظُّهْرَ رَكْعَتَيْنِ فَقِيلَ صَلَّيْتَ رَكْعَتَيْنِ فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ  

The Messenger of Allah ﷺ prayed Zuhr with two rak'ahs, then said the salam. They said: "Has the prayer been shortened?" So he stood up and prayed two rak'ahs, then he said the salam, then he prostrated twice.  

أَنَّ رَسُولَ اللَّهِ ﷺ صَلَّى صَلاَةَ الظُّهْرِ رَكْعَتَيْنِ ثُمَّ سَلَّمَ فَقَالُوا أَقُصِرَتِ الصَّلاَةُ فَقَامَ وَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ  

Abu Hurairah reported; The Prophet ﷺ offered the noon prayer and he gave the salutation at the end of two rakahs. He was asked. Has the prayer been shortened ? then he offered two rakahs of the prayer and made two prostrations (at the end of it).  

أَنَّ النَّبِيَّ ﷺ صَلَّى الظُّهْرَ فَسَلَّمَ فِي الرَّكْعَتَيْنِ فَقِيلَ لَهُ نَقَصَتِ الصَّلاَةُ فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَجَدَ سَجْدَتَيْنِ  

The Messenger of Allah ﷺ prayed Zuhr with two rak'ahs, then said the salam. They said: "Has the prayer been shortened?" So he stood up and prayed two rak'ahs, then he said the salam, then he prostrated twice. (Using translation from Nasāʾī 1227)   

أَنَّ رَسُولَ اللهِ ﷺ صَلَّى الظُّهْرَ رَكْعَتَيْنِ ثُمَّ سَلَّمَ قَالُوا قَصُرَتِ الصَّلَاةُ؟ قَالَ فَقَامَ فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ بَعْدَ مَا سَلَّمَ  

The Messenger of Allah ﷺ prayed Zuhr with two rak'ahs, then said the salam. They said: "Has the prayer been shortened?" So he stood up and prayed two rak'ahs, then he said the salam, then he prostrated twice. (Using translation from Nasāʾī 1227)   

أَنَّ رَسُولَ اللهِ ﷺ صَلَّى الظُّهْرَ رَكْعَتَيْنِ ثُمَّ سَلَّمَ فَقِيلَ لَهُ نَقَصَ مِنَ الصَّلَاةِ؟ فَصَلَّى رَكْعَتَيْنِ أُخَرَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ  

[Machine] The Prophet ﷺ prayed three units (rak'ahs) and then he said the salaam. It was said to him, so he stood up and prayed another unit, then he said the salaam. After that, he performed two prostrations while he was sitting.  

أَنَّ النَّبِيَّ ﷺ صَلَّى ثَلَاثَ رَكَعَاتٍ فَسَلَّمَ فَقِيلَ لَهُ فَقَامَ فَصَلَّى رَكْعَةً فَسَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ وَهُوَ جَالِسٌ  

The Messenger of Allah ﷺ prayed Zuhr with two rak'ahs, then said the salam. They said: "Has the prayer been shortened?" So he stood up and prayed two rak'ahs, then he said the salam, then he prostrated twice. (Using translation from Nasāʾī 1227)  

أَنَّ رَسُولَ اللهِ ﷺ صَلَّى الظُّهْرَ رَكْعَتَيْنِ ثُمَّ سَلَّمَ فَقَالُوا أَقَصُرَتِ الصَّلَاةُ فَقَامَ «فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَيْنِ»  

" أَنَّ رَسُولَ الله ﷺ صَلَّى بالنَّاسِ رَكعَتَينِ فَسَهَا فَسَلَّمَ، فَقَالَ لَهُ رَجُل يُقَالُ لَهُ ذُو الْيَدَيْنِ: نَقَصَتِ الصَّلاَةُ؛ فَقَالَ: لاَ، فَصَلَّى رَكْعَتَيْنِ أُخْرَاوَيْنِ ثُمَّ سَلَّمَ، ثُمَّ سَجَدَ سَجْدَتَيْنِ، ثُمَّ سَلَّمَ".