What are the missing numbers in the pyramids?
A little bit of algebra explains this 'magic'. Ask a friend to pick 3 consecutive numbers and to tell you a multiple of 3. Then ask them to add the four numbers and multiply by 67, and to tell you the last two digits of her answer. Now you can really amaze her by giving the whole answer and the three consecutive numbers used at the start.
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 a
total of 15 with 6 odd numbers?
Arrange the numbers 1 to 16 into a 4 by 4 array.
Repeat this process twice more choosing from the remaining
This should leave you with one number remaining, circle this one
Why do they always add up to 34 whatever way you choose your