Like 5jj says, it's impossible to say without knowing what prepositions you're teaching. One game I like to do with younger children is to simply have a selection of objects (usually vocab from earlier in the lesson) and a selection on things to put them in/on/under/next to/etc. I then say a sentence (e.g. the ball is on the chair) and the students race to put the correct object into the correct position. But that's prepositions of position. It doesn't work for prepositions of movement or prepositions of time, for example.
Also just to let you know, I'd find it easier to answer if you mentioned an age and level of English rather than a grade. I don't know what grades refer to in the Israeli education system.