In my second year of teaching, I really got into using concrete materials with my class of Year 3s. I'd started using them towards the end of the previous year but didn't really get going properly until the new academic year.
It was my second year, I'd finished my NQT year and I knew what I was doing!
My first mistake was expecting children who had barely seen base 10 before to not want to play with it. In my eagerness to hand over this fantastic resource that I had found buried, unloved in the maths cupboard, I had clearly forgotten that I was working with children. Silly me.
Fortunately (being a big brave RQT) I was able to abandon the lesson and let them play (whilst keeping everything crossed that no-one from SLT would walk in and ask why there was base 10 all over my classroom floor). The second lesson (and subsequent lessons) went much more smoothly because I gave the children chance to play. It is so easy to forget that these bits of colourful plastic that we see as amazing tools for teaching and developing understanding, to children, appear to be amazing tools for making castles, fields and (inevitably) guns.
Needless to say, by my third year I had learnt my lesson. My first maths lesson of the year was quite simply a case of 'Here's the base 10 and place value counters, have a play.' And in the second lesson I gave them challenges. This successfully got most of it out of their systems (although the odd tower and gun would appear throughout the year - children will be children).
As teachers it is so important for us to remember that our pupils are first and foremost children and children like (and need) to play.
Children want to play with equipment. Let them.