Six days of Shawwal
مَنْ صَامَ رَمَضَانَ ثُمَّ أَتْبَعَهُ سِتًّا مِنْ شَوَّالٍ كَانَ كَصِيَامِ الدَّهْرِ
Man sama Ramadana thumma atba'ahu sittan min Shawwalin kana ka-siyami-d-dahr.
"Whoever fasts Ramadan and follows it with six days of Shawwal, it is as if he fasted the whole year."
Narrated by Abu Ayyub al-Ansari. Sahih Muslim 1164
A short reflection
One month equals ten by the rule of ten-fold reward; six more equal sixty; together they are a year. Mathematics from a Merciful Lord.