All of the problems in my multi-grade database of 42,500+ problems are of 4 difficulty levels--level 1 being the simplest and level 4 being the most difficult. These particular problems are ALL of the ones at this level in the various NBT Domain standards.
TARGET STUDENTS: gifted classes, gifted individual students, students who want extra challenges, extra credit, end-of-semester challenge, summer camps, math clubs, elective math classes, etc.
[The problems in All WORKSHEETS and PREVIEWS are printed in difficulty (1 [easy], 2 [not so easy], 3 [proficiency] up to 4 [mastery]) order within a skill. The actual difficulty level appears slightly to the left of the DK box of each problem in a very small font.]
You might also want to check out the Domain Summary
and Gifted/Challenging topics
for the NBT Domain.
Also, check out the many other items I have (and will be adding to) for grades through 5--grades covered by the NBT Domain.