The pattern
Cut one amount into equal shares. One number tells you what a share is worth.

Cut one amount into equal slices, and let a stated number fix what one slice is worth. Every other slice is worth the same, because they were cut equal. It is the plainest bar model there is, one whole cut up, with a single number pinning the size of a slice. Nothing is transferred and nothing changes hands.
A single amount is split by a ratio, a fraction or a percentage. One extra number gives you the leftover, the difference, or the value of one share.
Children match the given number to the wrong number of shares, using the whole bar when the number covers only the leftover or the difference between two people's shares.
Filed under a different pattern, but this one is part of the working.
All the problem patterns → · the revision list
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
A PDF, and a note when new solutions go up.