From those who read a poster asking them to join the school's Number Sense team to the seasoned competitor eyeing State medals, this book serves as a guide and as inspiration, to not only pique interest but to build a foundation on. You'll find in this book a step-by-step guide on how-to solve Number Sense problems and prepare you for any mental math competitions. There are over 80 mental math techniques are explained in this book, and over 750 problems to learn, train, and improve with. Just a note: as fun as it is to learn new tricks and techniques on PEMDAS, Squares, GCD & LCM, Remainder, Higher Order Exponents, Roots, Primes & Divisors, Roman & Complex Numbers, Factorials & Combinations, Sequences, Memorization, Fractions, Decimals, Bases, Linear & Quadratic Equations, Sets, Logarithms, Matrices and many more. It's just as important to master them and implement them in full-length tests! I wish you all the best of luck, and happy computing!