Today I'd also found a link to the Cuisenaire Rods manipulative on the NRich site, which is absolutely fantastic. I remember discovering a dusty old box of rods in the resource cupboard during my NQT year, digging them out and then not really doing anything relevant with them because I didn't have a) the time or b) the experience to work out how to use them without just confusing the pupils more. I'd always been determined to go back and check them out properly though, particularly with the links to the work I've been doing with algebra tiles.
Unfortunately, without delving further into work on equations, you can't really represent subtraction or division. Despite this, I think using the rods might be a great way into a topic that pupils find really difficult - I'd probably have a play with these for a couple of lessons before moving on to algebra tiles and introducing squares.
Also unfortunately, I am no longer at the school with the dusty box of Cuisenaire rods in the stock cupboard, and as far as I know we don't have any kicking around anywhere at my current place, so I'll be playing with the manipulative only. However, I am pretty tempted by this funky set of fridge magnets on Amazon...!
EDIT: I've now written a resource to test out when I get back to school; I'm probably going to leave the second slide to start with, as I don't want to muddy the waters by teaching equations and expressions at the same time.
(Image credit: By Celcom, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=9511548)