Comparing and ordering numbers

problem
Favourite

Consecutive Seven

Age

11 to 14

Challenge level

Can you arrange these numbers into 7 subsets, each of three numbers, so that when the numbers in each are added together, they make seven consecutive numbers?
problem
Favourite

Farey Sequences

Age

11 to 14

Challenge level

There are lots of ideas to explore in these sequences of ordered fractions.
problem
Favourite

Difference Sudoku

Age

14 to 16

Challenge level

Use the differences to find the solution to this Sudoku.
problem
Favourite

Giants

Age

16 to 18

Challenge level

Which is the bigger, 9^10 or 10^9 ? Which is the bigger, 99^100 or 100^99 ?
problem

Fractions Made Faster

Age

7 to 11

Challenge level

Use the fraction wall to compare the size of these fractions - you'll be amazed how it helps!
problem

Move a Match

Age

7 to 11

Challenge level

How can you arrange these 10 matches in four piles so that when you move one match from three of the piles into the fourth, you end up with the same arrangement?
problem

Rachel's Problem

Age

14 to 16

Challenge level

Is it true that $99^n$ has 2n digits and $999^n$ has 3n digits? Investigate!
problem

Fair Exchange

Age

5 to 7

Challenge level

In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?
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Matching Numbers for Two

Age

5 to 7

Challenge level

Matching Numbers game for an adult and child. Can you remember where the cards are so you can choose two which match?
problem

Unexpected Ordering

Age

5 to 7

Challenge level

Watch the video of Fran re-ordering these number cards. What do you notice? Try it for yourself. What happens?