Ready to Learn: K-2 Subtraction Flash Cards: Includes 48 Cards to Practice Subtraction Skills!These subtraction flash cards in the Ready to Learn series will help young math students from kindergarten to second grade (ages 4 to 8) strengthen their math skills. Help children master the basics of subtraction with Ready to Learn: K 2 Subtraction Flash Cards. Half of the cards in this 48 card set show equations vertically, and the other half horizontally, so as to familiarize beginning math students ages 4 to 8 with the two most common ways theyll