In this 7-sandwich: 7 1 3 1 6 4 3 5 7 2 4 6 2 5 there are 7 numbers between the 7s, 6 between the 6s etc. The article shows which values of n can make n-sandwiches and which cannot.
Square numbers can be represented as the sum of consecutive odd
numbers. What is the sum of 1 + 3 + ..... + 149 + 151 + 153?
Read all about Pythagoras' mathematical discoveries in this article written for students.
Alison, Bernard and Charlie have been exploring sequences of odd and even numbers, which raise some intriguing questions...
Four bags contain a large number of 1s, 3s, 5s and 7s. Pick any ten numbers from the bags above so that their total is 37.
Use algebra to reason why 16 and 32 are impossible to create as the
sum of consecutive numbers.
Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?
There are exactly 3 ways to add 4 odd numbers to get 10. Find all
the ways of adding 8 odd numbers to get 20. To be sure of getting
all the solutions you will need to be systematic. What about. . . .
Great Granddad is very proud of his telegram from the Queen
congratulating him on his hundredth birthday and he has friends who
are even older than he is... When was he born?
Place the numbers 1, 2, 3,..., 9 one on each square of a 3 by 3 grid so that all the rows and columns add up to a prime number. How many different solutions can you find?
Explore the relationship between simple linear functions and their
Follow-up to the February Game Rules of FEMTO.
A new card game for two players.
Is this a fair game? How many ways are there of creating a fair
game by adding odd and even numbers?