### There are 20 results

Broad Topics >

Decision Mathematics and Combinatorics > Algorithms

##### Age 14 to 18 Challenge Level:

How can you quickly sort a suit of cards in order from Ace to King?

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

Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?

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

When the number x 1 x x x is multiplied by 417 this gives the
answer 9 x x x 0 5 7. Find the missing digits, each of which is
represented by an "x" .

##### Age 14 to 18 Challenge Level:

How would you judge a competition to draw a freehand square?

##### Age 14 to 16 Challenge Level:

Imagine a strip with a mark somewhere along it. Fold it in the middle so that the bottom reaches back to the top. Stetch it out to match the original length. Now where's the mark?

##### Age 14 to 16 Challenge Level:

However did we manage before calculators? Is there an efficient way
to do a square root if you have to do the work yourself?

##### Age 14 to 16 Challenge Level:

What day of the week were you born on? Do you know? Here's a way to
find out.

##### Age 14 to 16 Challenge Level:

Keep constructing triangles in the incircle of the previous triangle. What happens?

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

Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?

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

Amazing as it may seem the three fives remaining in the following
`skeleton' are sufficient to reconstruct the entire long division
sum.

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

This addition sum uses all ten digits 0, 1, 2...9 exactly once.
Find the sum and show that the one you give is the only
possibility.

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

Find the numbers in this sum

##### Age 14 to 16 Challenge Level:

Vedic Sutra is one of many ancient Indian sutras which involves a
cross subtraction method. Can you give a good explanation of WHY it
works?

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

This challenge is to make up YOUR OWN alphanumeric. Each letter
represents a digit and where the same letter appears more than once
it must represent the same digit each time.

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

A 3 digit number is multiplied by a 2 digit number and the
calculation is written out as shown with a digit in place of each
of the *'s. Complete the whole multiplication sum.

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

The number 10112359550561797752808988764044943820224719 is called a
'slippy number' because, when the last digit 9 is moved to the
front, the new number produced is the slippy number multiplied by
9.

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

Countries from across the world competed in a sports tournament. Can you devise an efficient strategy to work out the order in which they finished?

##### Age 14 to 16 Challenge Level:

It's like 'Peaches Today, Peaches Tomorrow' but interestingly
generalized.

##### Age 11 to 16

Scheduling games is a little more challenging than one might desire. Here are some tournament formats that sport schedulers use.

##### Age 5 to 14

Read this article to find out the mathematical method for working out what day of the week each particular date fell on back as far as 1700.