This part of the lesson is connected to your Learning Intentions for the lesson. https://curriculum.gov.bc.ca/curriculum/mathematics
Use any one of these to kick off your unit of study or as a check in part way through. Otherwise your activator might be a quick review of what you have done and then continue with the study. https://gfletchy.com/3-act-lessons
This site has many problem posing pictures/videos that do not guide the students step by step through the solving. It makes them be real problem solvers! On his site as well are links to many other terrific math educators sites that pose good problems.
Your math text book has many terrific problems to introduce and to practice concepts. Remove much of the excess language and or the numbers and have students figure out what the answers could be.