These red and blue numbers in 5 gram weight increments (5 grams to 50 grams) let you teach about number value, weights and early number skills. When used with Primary Bucket Balance (LER1521, sold separately) you can demonstrate 2 is less than 8; or 2 + 4 in one bucket is equal to 6 in the other. Each number is spelled out on the back to reinforce word recognition and odd and even numbers are color coded. Each number measures 3" x 2" x .5".