One strategy students can use to solve 2 digit subtraction problems (with and without regrouping) is by using base ten block manipulatives. This is a concrete method for teaching students how to subtract larger numbers so they develop a conceptual understanding. After you use the manipulatives, you can use these worksheets to reinforce their understanding. Students draw base ten blocks and show how they decompose a ten to regroup into ten ones. There are 2 different methods with teacher's guides for you to use. I teach both methods to my students and let them decide which one they understand and like best. There are also worksheets where the base ten blocks are drawn and students count, write the number, and subtract. There are 2 pages of word problems for students to solve with their quick drawings of base ten blocks.