I have to teach a 20 minute session on problem solving with money and I have selected the learning objective already but have 2 really different lesson ideas... 1. A maths trail where children will be have to solve word problems and I might add a competitive nature and have them crack a code, so add an element of competition. or 2. A maths investigation but I don't think I'd be doing much teaching as such in an activity like this but I would aim to make it relevant and purposeful to the children. What do you think?