These are amazing websites to use when planning common core math lessons. Lots of ideas for lessons and assessments.
This first set of links is from Howard County Schools. We discussed these sites last year in PLCs. These sites give you access to ideas for instructions and lesson plans for most of the common core standards that we will be teaching this year:
Kindergarten
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
This next links takes you to commoncoresheets.com, and this website provides tons of GREAT worksheets for every common core standard, at every level. This is a great place to get seatwork, homework, small group pages, or even common assessments.
All Grade Levels
It would also be a great idea for teachers to all look at the grade level before/after their own before they plan a lesson. Vertical planning and thinking will benefit the students as well as the teacher.