The Abacus That Teaches Children Addition and Subtraction The new, revolutionary way for kids to learn adding and subtracting! Smart Abacus™ teaches children in Grades PreK-1 addition, subtraction, and how to write numerals. The app is revolutionary in its simplicity! This hand-on approach uses colorful, fun, step-by-step lessons and provides plenty of guided practice. Children learn basic addition and subtraction of single digit numbers and then advance to addition of two digit numbers and subtraction involving regrouping. Smart Abacus™ is available for most large phones, tablets, and computers. For even more mathematical learning and practice, use Smart Abacus™ with our award-winning Mathematical Reasoning™ books! Grades: Preschool, Prekindergarten, Kindergarten, and 1st Grade Subjects: Mathematics and Critical Thinking Author: Michael Baker Features - Video tutorial for guided instruction - Teaching mode with 5 addition lessons and 5 subtraction lessons (in paid version*) - Teaches regrouping when subtracting - Trace your answer to learn to write numerals - Calculator mode for independent practice (in paid version*) - Free and Ad-free