Factors and multiples

problem
Mystery matrix

Age

7 to 11

Challenge level

Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.
problem
In the money

Age

7 to 11

Challenge level

One quarter of these coins are heads but when I turn over two coins, one third are heads. How many coins are there?
problem
Fractions in a box

Age

7 to 11

Challenge level

The discs for this game are kept in a flat square box with a square hole for each. Use the information to find out how many discs of each colour there are in the box.
problem
Two primes make one square

Age

7 to 11

Challenge level

Can you make square numbers by adding two prime numbers together?
problem
Sets of numbers

Age

7 to 11

Challenge level

How many different sets of numbers with at least four members can you find in the numbers in this box?
problem
A square deal

Age

7 to 11

Challenge level

Complete the magic square using the numbers 1 to 25 once each. Each row, column and diagonal adds up to 65.
problem
Sets of four numbers

Age

7 to 11

Challenge level

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?
problem
Crossings

Age

7 to 11

Challenge level

In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?
problem
Multiples grid

Age

7 to 11

Challenge level

What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?
problem
Factor-multiple chains

Age

7 to 11

Challenge level

Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?