This file includes a cover page with the common core state standard that is aligned to the problems, which is CCSS.Math.Content.4.NBT.B.4. The problems are great for revisiting/reviewing (during the unit, or right before state tests) estimating, addition and subtraction with trading and borrowing. There are 8 estimate/addition problems and 8 estimate/subtraction problems as well as 7 word problems mixed addition and subtraction. These sheets could be given together in a packet or separate. There is an answer key included.
These worksheets can be used with my Math Place Value Worksheets