Understanding GMAT fast math tricks is essential for GMAT success. These operations appear in nearly every quant question. This comprehensive guide covers everything you need to know, from multiplication and division shortcuts to practice drills for speed improvement.
Divide by 5 by dividing by 10 then multiplying by 2
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Breaking numbers into components
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on breaking numbers into components consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Using known products to derive others
| Technique | How It Works | Example | Time Saved |
|---|---|---|---|
| Divide by 5 | Divide by 10, multiply by 2 | 350÷5 → 350÷10=35 → 35×2=70 | ~10 seconds |
| Multiply by 5 | Divide by 2, multiply by 10 | 48×5 → 48÷2=24 → 24×10=240 | ~10 seconds |
| Percentage from 10% | Find 10%, then build up | 35% of 80: 10%=8, 30%=24, 5%=4, total=28 | ~15 seconds |
| Complement Subtraction | Add to round, then adjust | 117-98: 117-100+2 = 19 | ~5 seconds |
| Number Splitting | Break into easy components | 16×25: 16×100÷4 = 400 | ~10 seconds |
| Backsolving | Test answer choices | Start with middle answer choice | ~30 seconds |
Worked Example
Consider this scenario related to multiplication and division shortcuts: a student needs to apply the concepts discussed in this section.
Building percentages from 10%, 5%, and 1%
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Using multipliers for increases and decreases
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on using multipliers for increases and decreases consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Common fraction-to-decimal conversions
Worked Example
Consider this scenario related to fraction and percentage mental math: a student needs to apply the concepts discussed in this section.
Rounding to simplify
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Using ranges to eliminate options
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on using ranges to eliminate options consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
When estimation is sufficient vs exact calculation
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on when estimation is sufficient vs exact calculation consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Times tables through 12
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Common Pythagorean triples 3-4-5 and 5-12-13
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on common pythagorean triples 3-4-5 and 5-12-13 consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Decimal approximations of sqrt(2), sqrt(3), and pi
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on decimal approximations of sqrt(2), sqrt(3), and pi consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
| Category | Values to Know | Why They Help |
|---|---|---|
| Times Tables | Through 12 x 12 | Fast multiplication saves 10-15 seconds per question |
| Perfect Squares | 1-15 (1, 4, 9, 16... 225) | Recognize patterns in algebra and geometry |
| Pythagorean Triples | 3-4-5, 5-12-13, 8-15-17 | Solve right triangle problems instantly |
| Special Triangle Ratios | 30-60-90: 1-√3-2; 45-45-90: 1-1-√2 | Skip calculations in geometry |
| Key Square Roots | √2≈1.414, √3≈1.732, √5≈2.236 | Quick estimation for irrational numbers |
| Powers of 2 | 2,4,8,16,32,64,128,256,512,1024 | Essential for combinatorics and exponents |
| Powers of 3 | 3,9,27,81,243,729 | Useful for exponent problems |
| Common Fractions | 1/3=.333, 1/6=.167, 1/7=.143, 1/8=.125 | Faster percentage calculations |
Backsolving from answer choices
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Picking smart numbers for variables
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on picking smart numbers for variables consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Recognizing answer choice patterns
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on recognizing answer choice patterns consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Solve everything mentally during study sessions
When approaching this aspect of GMAT fast math tricks, focus on building consistent habits that compound over time. Many successful test-takers find that dedicating focused attention to this area yields significant score improvements within weeks of targeted practice.
Speed drill exercises
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on speed drill exercises consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Tracking improvement over time
Developing proficiency in this area requires deliberate practice and strategic focus. Students who systematically work on tracking improvement over time consistently report measurable improvements in their GMAT performance within 2 to 4 weeks of targeted effort.
Test your understanding with these practice questions designed to reinforce the concepts covered in this guide.
No, calculators are not allowed on the GMAT Quantitative Reasoning section. This is why mental math and fast calculation techniques are essential skills. Calculators are only available in the Data Insights section for certain question types.
Effective mental math techniques can save 5 or more minutes across the GMAT Quantitative section. With 21 questions in 45 minutes, saving even 15 seconds per question through faster calculations gives you over 5 extra minutes for the most challenging problems.
Memorize times tables through 12, the Pythagorean triples 3-4-5 and 5-12-13, special triangle side ratios, decimal approximations of square root of 2 (1.414), square root of 3 (1.732), and pi (3.14), plus powers of 2 and 3 through at least the sixth power.