I got these robotic toy kits for two kids 6 and 8 years old. I have gotten a few robotic toy kits before, as the toy allows the kids to gain hands-on experience in assembling things and learn some basic concepts of science and engineering with adults' help. In this case, dual energy source from solar energy, and stored chemical energy from battery converted into mechanical energy to power the robot toy. Also the kids learn how gears and wheels work. The toy is a 15 in 1 set, and 15 different robots can be built, except disassembling is needed going from one to another (a negative). The kids will be awarded with a finished toy that they can play with. I do not expect the kids to complete all 15 versions as it will take a long time and disassembling one to go to another may break some parts. It would be good if they could try out a few interesting ones.
I do not expect kids to fully assemble them on their own. Usually, I got them and guided them and figured out the steps along the way. Taught them some things about mechanical and electrical concepts during the assembly to grow their interest and knowledge. It is not a one time thing and hopefully after a few toy assemblies, the kids will understand the concept, and how to assemble things better and better.