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## 'Pyramids' printed from http://nrich.maths.org/

When completing a pyramid, each number above the base is made up
from the sum of the two supporting it.

**(i)**
What are the missing numbers?

**(ii)**
What is the value of a?

**(iii)**
Find the value of *b* for which the pyramid can be filled
with whole numbers in this pattern. With this value of *b*
find some different ways of doing so.

**(iv)**
Find eight different pairs of positive values of *x* and
*y* . How many solutions are there altogether?

Can you find a relationship between *x* and *y*
?