Montessori 1000 ChainA Thousand Chain. A set of small labels, 10 to 90 in blue, 100 to 900 in red, 1000 to 9000 in green. A Thousand Cube. Help the child realize how much bigger one hundred are than one ten, and how much bigger one thousand is than one hundred. Help the child grasp the conservation of number and reversibility. Introduce the child to counting in tens.|CONTROL OF ERROR:|| |AGE:||3 – 6 years approx.