### There are 13 results

Broad Topics >

Numbers and the Number System > Common factors

##### Age 7 to 11 Challenge Level:

This big box multiplies anything that goes inside it by the same number. If you know the numbers that come out, what multiplication might be going on in the box?

##### Age 7 to 11 Challenge Level:

Find the words hidden inside each of the circles by counting around
a certain number of spaces to find each letter in turn.

##### Age 11 to 14 Challenge Level:

Given the products of adjacent cells, can you complete this Sudoku?

##### Age 7 to 11 Challenge Level:

Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

##### Age 7 to 14 Challenge Level:

Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?

##### Age 11 to 14 Challenge Level:

Follow this recipe for sieving numbers and see what interesting patterns emerge.

##### Age 11 to 14 Challenge Level:

How many integers between 1 and 1200 are NOT multiples of any of
the numbers 2, 3 or 5?

##### Age 11 to 14 Challenge Level:

I put eggs into a basket in groups of 7 and noticed that I could
easily have divided them into piles of 2, 3, 4, 5 or 6 and always
have one left over. How many eggs were in the basket?

##### Age 11 to 14 Challenge Level:

A and B are two interlocking cogwheels having p teeth and q teeth respectively. One tooth on B is painted red. Find the values of p and q for which the red tooth on B contacts every gap on the. . . .

##### Age 11 to 14 Challenge Level:

What is the smallest number of answers you need to reveal in order
to work out the missing headers?

##### Age 11 to 14 Challenge Level:

Can you find a relationship between the number of dots on the
circle and the number of steps that will ensure that all points are
hit?

##### Age 7 to 11 Challenge Level:

What happens when you turn these cogs? Investigate the differences
between turning two cogs of different sizes and two cogs which are
the same.

##### Age 11 to 14 Challenge Level:

Here is a chance to create some Celtic knots and explore the mathematics behind them.