One of the ways we decide between appropriate development and strong performance with addition is whether or not students understand missing addends. I created this activity awhile back to engage students and to check their understanding.
Students love choice so I created 2 different recording sheets for them to choose from. There is an I can... card to build student independence. Students choose a number sentence card then find a bolt that has the missing number to fix the equation. Here's a peek at what's included: