We used the rods. I think I purchased them for DD when she was about 3 years old. At 2.5 she started counting coins up through 50 out of the blue and completely untaught. I introduced the rods as a dining room table toy. She took right to them. She caught on to their names right away, and it was a great way to show her how to measure things and compare. If she did not remember that the orange rod was a ten rod, she could measure them with one rods, or she could compare the orange rod to two five rods, etc.
I was actually quite surprised how intuitive it was for her. It was not to me, but I got the hang of it. She just played with them, making trains, patterns, and calling the 3 rods preschoolers, the 4 rods pre-Kers, the 5 rods kindergartners, etc.
When she started to add above ten, the rods were just amazing. She immediately manipulated them in such a way that made it easier for her to "see". For example, she could measure that an 8+7 was the same length as a 10+5, and she could break it down further as an 8+2+5. I think the rods are great for exploring and internalizing--not rote memorization.
I never really taught with them. They just stayed on the dining room table until they got cycled out for something else. She would play with them, and I might yell over to figure out 8+7.
They were great for my not very visual DD. It really helped her see things in concrete ways when she was more inclined to just memorize facts. Addition, subtraction, multiplication, division, and fractions have been explored through these rods. It was just luck that I stumbled onto them. I am thoroughly happy that I did.
