These red and blue numbers in 5 gram weight increments (5 g to 50 g) let you teach about number value, weights and early number skills. When used with Primary Bucket Balance 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. Details: Red and blue 3" x 2" x 0.5" each 5 gram weight increments (5 g to 50 g) Odd and even numbers are color coded Each number is spelled out on the back to reinforce word recognition For ages 3 and up