See Graham Fletcher's website/blog for 3 Act Tasks and other amazing math resources.

From the NC2ML website:

The North Carolina Collaborative for Mathematics Learning (NC2ML) aims to support NC math educators in implementing the revised mathematics content standards in ways that align with what we know from research on students' mathematical thinking, mathematics teaching, and teacher learning.  To do so, we bring together Mathematics educators to co-design research-based resources and professional learning opportunities.

This is a link to the North Carolina Department of Instructions Standard Course of Study for Mathematics.  On this page you will find links to all of the grade level specific standards and unpacking documents.