Alphabet Soup

This challenge is to make up YOUR OWN alphanumeric. Each letter represents a digit and where the same letter appears more than once it must represent the same digit each time.
Age
11 to 14
Challenge level
filled star empty star empty star
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

This challenge is to make up YOUR OWN word-arithmetic challenge.

Each letter represents a digit and where the same letter appears more than once it must represent the same digit each time.

The hard part is to make up some message rather than just using any old letters. Send in your word-arithmetic challenge, together with at least one solution to it.

Another challenge is to discover if the puzzle has just one solution or many. Here are two easy examples; they are just addition sums and you may be more inventive and make up subtractions, multiplications or divisions:

 

  N R I C H
+ S T A R S
  M A T H S
 
  M A T H
+ E M A T
  I C A L


Lastly, can you prove that

  N R I C H
+ M A T H S
  S T A R S

cannot be made to work?