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There are at least twelve solutions to the addition sum
M | U | M | |
+ | D | A | D |
-- | -- | -- | -- |
K | I | D | S |
You have to replace the seven letters by seven numbers. How many solutions can you find? How many solutions are there?
An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some other possibilities for yourself!