Do you want to double or triple the speed with which you calculate? How to Calculate Quickly is a tried and true method for helping you in the mathematics of daily life--addition, subtraction, multiplication, division, and fractions.
The author can awaken for you a faculty which is surprisingly dormant in accountants, engineers, scientists, businesspeople, and others who work with figures. This is "number sense"--or the ability to recognize relations between numbers considered as whole quantities. Lack of this number sense makes it entirely possible for a scientist to be proficient in higher mathematics, but to bog down in the arithmetic of everyday life.
This book teaches the necessary mathematical techniques that schools neglect to teach: Horizontal addition, left to right multiplication and division, etc. You will learn a method of multiplication so rapid that you'll be able to do products in not much more time than it would take to write the problem down on paper.
This is not a collection of tricks that work in only a very few special cases, but a serious, capably planned course of basic mathematics for self-instruction. It contains over 9,000 short problems and their solutions for you to work during spare moments. Five or ten minutes spent daily on this book will, within ten weeks, give you a number sense that will double or triple your calculation speed.

The Plan of This Book
ADDITION
Addition in General
"Adding Single Columns by Pairs, starts on"
"Adding Single Columns by Trios, starts on"
"Mental Addition of Large Numbers, starts on"
"Two-Column Addition, starts on"
SUBTRACTION
Subtraction in General
"Left-to-Right Subtraction, starts on"
MULTIPLICATION
Multiplication in General
"Factoring, starts on"
"Direct Multiplication by Numbers Greater than 12, starts on"
"Multiplying Three Figures by One, starts on"
"Multiplying Two Figures by Two, starts on"
"Multiplying Three Figures by Two, starts on"
"Multiplying Three Figures by Three, starts on"
DIVISION
Division in General
"Direct Division by Numbers Greater than 12, starts on"
"Mental Division of Large Numbers, starts on"
"Division by Three Figures, starts on"
"Division by Two Figures, starts on"
FRACTIONS
Fractions in General
"Addition and Subtractions of Fractions, starts on"
DECIMALS
Decimals in General
"Decimal Equivalents of Fractions, starts on"
SHORT CUTS
Horizontal Addition
Combined Addition and Subtraction
Multiplying by a Near Number
Aliquot Parts in Multiplication
Simplifying the Multiplier
Multiplication by Factoring
Factors between 11 and 19
Multiplying by 11
"Multiplying by 21, 31, 41, etc."
"Squares of Numbers, starts on"
"Multiplying When Corresponding Orders Are Alike, starts on"
Multiplying a Sum by a Difference
"Multiplications Involving Fractions, starts on"
Aliquot Parts in Division
Cubes of Numbers
Algebraic Multiplication
Table of Prime and Composite Numbers
ANSWERS