EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.
Find a great variety of ways of asking questions which make 8.
If you had any number of ordinary dice, what are the possible ways
of making their totals 6? What would the product of the dice be
From any ISBN code we can calculate a 'check total' by multiplying the digits in the code by $1, 2, 3, \ldots$ in order and adding these products. For example $0 - 04 - 823208 - 4$ gives $$(1\times0) + (2\times0) + (3\times4) + (4\times8) + (5\times2) + (6\times3) + (7\times2) +$$ $$+(8\times0) + (9\times8) + ( 10\times4) = 198$$
Try this for yourself with any ISBN number and the check total will always be divisible by 11. This calculation is used to check that the book number has been copied down accurately and thus to avoid errors in placing orders.
This solution was sent in by Abbas from Jack Hunt School, Peterborough, for a previous version of the problem, in which we asked you to calculate the missing digit in this ISBN: $$0 - 947?95 - 24 - 3$$.