Number operations & calculation methods

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

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Can you use the clues to complete these 5 by 5 Mathematical Sudokus?

I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?

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

How many solutions can you find to this sum? Each of the different letters stands for a different number.

Which set of numbers that add to 100 have the largest product?

A cinema has 100 seats. Show how it is possible to sell exactly 100 tickets and take exactly £100 if the prices are £10 for adults, 50p for pensioners and 10p for children.

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?

A jigsaw where pieces only go together if the fractions are equivalent.

Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 ÷ 360. How did this help?

Can all unit fractions be written as the sum of two unit fractions?

Here is a chance to play a fractions version of the classic Countdown Game.

Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?

Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?

Imagine a very strange bank account where you are only allowed to do two things...

How many different differences can you make?

Can you crack these cryptarithms?

How many ways can you find to put in operation signs (+, −, ×, ÷) to make 100?

Choose some fractions and add them together. Can you get close to 1?

Can you explain the strategy for winning this game with any target?

Can you find six numbers to go in the Daisy from which you can make all the numbers from 1 to a number bigger than 25?

Take a look at the video and try to find a sequence of moves that will untangle the ropes.

It would be nice to have a strategy for disentangling any tangled ropes...

In this game the winner is the first to complete a row of three. Are some squares easier to land on than others?

Different combinations of the weights available allow you to make different totals. Which totals can you make?

Just because a problem is impossible doesn't mean it's difficult...

Can you find ways to put numbers in the overlaps so the rings have equal totals?

Aisha's division and subtraction calculations both gave the same answer! Can you find some more examples?

Charlie and Abi put a counter on 42. They wondered if they could visit all the other numbers on their 1-100 board, moving the counter using just these two operations: x2 and -5. What do you think?

The Egyptians expressed all fractions as the sum of different unit fractions. Here is a chance to explore how they could have written different fractions.

Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?

The Egyptians expressed all fractions as the sum of different unit fractions. The Greedy Algorithm might provide us with an efficient way of doing this.

Find the sum of this series of surds.