3-5 Example

Some numbers can be written as a sum of consecutive positive integers, for example:

  6 = 1 + 2 + 3
15 = 4 + 5 + 6
     = 1 + 2 + 3 + 4 + 5

In small groups, find all numbers from 1-100 that can be written as a consecutive sum. Look for patterns as you work. Conjecture which numbers can and which cannot be expressed as a consecutive sum. How can some of the sums be used to find others?

Consider the following modifications for learners who need additional support, including English learners and students with special needs:

Ensure any modification does not reduce the cognitive demand of the task.