Some Examples!

simply fill add a number- nice easy one to start with....
   
introduce and reinforce that vocabulary....
   
time and mental teasers...
   
percentages, money, fractions, decimals, equivalents all in one go...
   
coordinates and magic squares....
   
dates...
   
exchange rates and averages....
   
missing numbers....
   
g, Kg, Lb, oz, L, ml - you decide...
   
mathematical notation and problems...
   
money, coins and change....
   
area and missing numbers/operators- including brackets...
   
properties of numbers....
   
money, mental problems, reasoning about numbers...
   
probability- enough said...
   
patterns, sequences and measures...
   
time- analogue and digital...