Put them in groups of 4. Surely one person in those 4 will understand what is being taught.

I teach third graders (8-9 year olds). I arrange their individual desks in groups of 4-5 with two people side-by-side- and then two facing them and maybe one on the end. I select students who are lower to put next to average students and then higher students with average or low students. I give them many opportunities to discuss ideas in partners next to them(elbow partners) and partners across from them (mirror partners). They can also discuss things as a whole group which I allow them to name their table together. I also set up a reading corner.with pillows and books of varying levels. If you have room, you can set up a writing table to publish their writing. It could contain various papers, pre-made blank books, envelopes, markers, crayons, hole punches and zig-zag scissors. I have lots more ideas but hopefully this will help for now...Good Luck!