This is an "I Have, Who Has" activity to help support 2.NBT.8. The students use these cards to mentally add either 10 or 100 to a given number and find the corresponding card with the answer to get the next question.
I use these in small groups, but whole group works as well. There are 40 cards total, alternating between 10 and 100.
My kids get great practice with these...I hope yours do too!