This book based on research at the University of New-Brunswick and University of Toronto gives ideas on how to meet the needs of students who are at different levels of development.  They use the concepts of open questions and parallel tasks.  With open-ended questions, students are able to solve concepts at their level of understanding and be creative with their answers,

The big mathematical ideas and related questions are asked at 3 different levels:

JK- grade 2

Grades 3-6

Grades 6-8

For example, in numeracy, one big idea is: There are many ways to represent numbers.

While a possible question is:

The answer is 42.  What is the question?

or

You add two fractions and the sum is 9/10.  What could the fractions be?