Fantastic ideas for lego maths games - fun learning! We did so much of this in Kindergarten - measuring with Lego, Popsicle sticks, kids!
use a hanger to make a balance Math with Legos: How many Legos does it weigh? Now here's a math game that would keep my boys engaged.
The Imagination Tree: Handprint Measuring and Number Lines! Trace your preschooler's hand over and over. Let them color it, cut it out, then use to measure. Neat idea for SLC (measuring, numbers, etc)