It would be a good idea if you always start your lesson with a warm up. I recommend you to use an estimation everyday where kids can think freely and try to connect maths with real life situations. I have been using a wonderful website for over two years:
http://www.estimation180.com
The results are amazing. Students get suddenly engaged in the lesson and get focus for maths easily!!!
However you should let them do. At the beginning they will just guess. Be patient, little by little they will develop a better understanding and they will start techniques such as proportions or even more creatives ones. They will mix geometry with fractions to solve a problem and all of these in a real life context.
Do not hesitate to use that technique in your class and share your results with us!!!!
