Here's this week's collection. Answers & extensions here. Why not discuss the problems on Twitter using #SundayAfternoonMaths or on Reddit.
In a ‘ninety nine’ shop, all items cost a number of pounds and 99 pence. Susanna spent £65.76. How many items did she buy?
Find two digits a and b such that ab in base 10 is equal to ba in base 4?
Find two digits c and d such that cd in base 10 is equal to dc in base 7?
Find two digits e and f such that ef in base 9 is equal to fe in base 5?