Estimation: Put 10 plastic farm animals in a jar and 3 plastic farm animals in a second jar. Write on the second jar, "If this is 3, then"…. Write on the first jar (the one with 10 plastic animals), How many is this?" Each child examines the jar with the known number, estimates the number in the second jar, writes down the estimate and then, checks the guess by counting the animals in the first jar.