Two-digit Targets
Stage: 1 Challenge Level: 
You have a set of the digits from 0 – 9. Can you arrange these in the 5 boxes to make two-digit numbers as close to the targets as possible?
Largest Even
Stage: 1 Challenge Level:
How would you create the largest possible two-digit even number from the digit I've given you and one of your choice?
One of Thirty-six
Stage: 1 Challenge Level:
Can you find the chosen number from the grid using the clues?
6 Beads
Stage: 1 Challenge Level:
If you put three beads onto a tens/ones abacus you could make the numbers 3, 30, 12 or 21. What numbers can be made with six beads?
Grouping Goodies
Stage: 1 Challenge Level:
Pat counts her sweets in different groups and both times she has some left over. How many sweets could she have had?
That Number Square!
Stage: 1 and 2 Challenge Level:
How quickly can you put back the numbers on the hundred square? What's the smartest way to do it?
Snail One Hundred
Stage: 1 and 2 Challenge Level:
This is a game in which your counters move in a spiral round the snail's shell. It is about understanding tens and units.
NRICH is part of the family of activities in the Millennium Mathematics Project.