This is a set of seatwork papers that I used during our unit of 2 digit addition and subtraction within 100. (1.NBT.4). The students used base ten blocks to solve each equation, and were directed to focus on when they had enough ones to make a trade for a new group of ten. Many of the worksheets prompt students to identify when a new group of ten would be made. The worksheets cover adding without new groups of ten being made, adding or subtracting multiples of 10, adding when a new group of 10 would be made, and mixed practice sheets.
Along with solving the equations, students are also asked to write an equation to match the pictures.
Hopefully these worksheets will work as well for you as they did for my students. They were very helpful in offering practice to follow the instruction that I provided in class and allowed me to see who required more practice and who had mastered those skills.