Paraphrasing for Math Word Problems (Changing sentence structure without changing meaning)

I'm working on Khan Academy's exercise framework, and more specifically, word problems.

When doing a word problem exercise, students often get the same word problem, only with numbers and names changed. This is not ideal, as students can quickly learn the pattern and extract relevant data without reading the entire problem.

Are there any ways of changing sentence structure without changing the meaning of the word problem? Any开发者_StackOverflow other ideas of how to solve this repetition problem are also welcomed.

When creating the word problem, use some sort of syntax to denote various equivalent phrases, as is done in article spinning sometimes. Then when displaying the word problem, pick randomly between them.

Example syntax:

[Name] {goes to the store and /goes to the market and /}{purchases/buys} [number] {apples/pears/bananas}. He {gives/sells/donates} [number] to [name]. {How many does he have now?/How many does he have left?/How many does he still have?}

2 example word problems that the syntax above could create:

Bob buys 8 bananas. He sells 5 to Alice. How many does he have left?

Harry goes to the market and purchases 19 pears. He gives 2 to Alex. How many does he have now?

For even more combinations, you could make it recursive.

Here's an article explaining a similar syntax to what I showed above; http://www.efficientarticlemarketing.com/article-spinning-tutorial-spinning-syntax-basics/