Math GeniusMental MathStrategies
Essential Strategies Series

Mental Math Strategies

The Essential Shortcut Playbook for Middle School Success

69 Strategies5 VolumesMastery ChecksCompetition Prep
Grades 5–8 ·Competition Ready · Print-Ready PDF
$20.00
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About This Book

Master fast calculation techniques that top students use every day. Each chapter teaches a single shortcut, proves why it works, then builds mastery with progressively harder practice sets. Perfect for test prep, competition warm-ups, or everyday class work.

Table of Contents

1 Basic Divisibility Rules
2 Powers of Two
3 Last-Digit Divisibility Tests — Easy Primes
4 Triangular Numbers
5 The 1/7 Repeating Decimal Cycle
6 Decimal Digits of p/11
7 Cyclic Last-Digit Patterns in Powers
8 The 9-9-10 Rule
9 Percent Building Blocks
10 Left-to-Right Addition
11 Compensation — Addition and Subtraction
12 Friendly Number Anchors — 25, 50, 75, 100
13 Mental Multiplication by Simple Fractions
14 Difference of Squares
15 Cross-Product for Proportions
16 Percentage Change
17 Sum of an Arithmetic Sequence
18 Halving and Doubling
19 Special Number Multipliers
20 Squares — Special Cases
21 Ratio Scaling
22 Estimation with Compatible Numbers
23 Modular Clock Arithmetic
24 Division by 9 and 11 via Digit Sums
25 Squares Near 50 and Near 100
26 Factor Decomposition
27 Squaring Any Two-Digit Number
28 Average via Anchor
29 Speed Multiplication Methods — x6, x7, x8
30 Square Root Linearization
31 GCF by Repeated Subtraction
32 Last-Digit Divisibility Tests — Medium Primes
33 Casting Out Nines
34 Prime Factorization Strategies
35 Number of Divisors
36 LCM from GCF
37 Place-Value Column Method
38 Compensation in Multiplication
39 Halving Chains and Reciprocal Division
40 Cube Root Estimation
41 Sum of Divisors
42 Last-Digit Divisibility Tests — Hard Primes
43 The Euclidean Algorithm for GCF
44 Vedic Cross-Multiplication
45 Squaring Any Three-Digit Number
46 Vedic Division
47 The Doomsday Algorithm — Day of the Week for Any Date
48 Square Roots by Long Division — Perfect Squares
49 Lattice Multiplication
50 Square Roots by Long Division — Non-Perfect Squares

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Why This Book?

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Infinite Variations

Every practice set uses our AI-powered generator — the same numbers never appear twice.

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Answers and Worked Methods

Every problem has an answer, and a full step-by-step solution for its method — nothing is left as just a number.

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Competition Aligned

Difficulty and style are calibrated to AMC 8 and MathCounts standards.

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Print Ready

Professionally typeset with LaTeX — sharp on any standard printer.