Consecutive numbers, arithmetic series, and geometric series can be added using shortcut methods.
Special techniques are provided for multiplying by digits, numbers ending in zeros, 11, 15, 25, 99, 125 and other useful numbers.
Quick methods are given for squaring numbers ending in 1, 5, 9, 25 and other special forms.
Methods for subtracting numbers from powers of 10 and the next highest power of 10.
Divisibility tests, division by 5, 15, 25, 125, 9 and division using factors.
Shortcut techniques for adding, subtracting, multiplying and dividing fractions and mixed numbers.
Fast methods for finding common percentages such as 16⅔%, 33⅓%, 37½%, 62½%, 66⅔% and 87½%.
The methods emphasize quick calculation, reduced intermediate work and performing calculations from left to right.
- Addition – 6 short cuts
- Multiplication – extensive shortcut techniques
- Subtraction – 2 short cuts
- Division – divisibility and factor methods
- Fractions, mixed numbers and percentages – 18 short cuts
- Do-It-Yourself short cuts – final section
