I looking for help. I'm working with a 5 year old in the Stanford EPGY program. She's progressed rapidly through K, 1, and the first half of 2nd in EPGY. But simultaneous equations seem to be a big stumbling block. She gets them but with difficulty and always by trial and error. Has anyone thought about manipulatives appropriate for whole number, 2 variable, linear, simultaneous equations?
I've thought about building a clear acrylic frame where various size disposable measuring cups can either sit above a shelf or through a whole in a shelf with only the thin rim supported by the shelf. Using pennies or candies provides the discreteness and leaves open the use of liquids later for fractional solutions.