What are the best arithmetic tricks to improve GMAT Quant speed and accuracy?

Question

Ranjan J · Accepted Answer

What worked for me was training my brain to handle calculations more flexibly instead of just mechanically solving everything.

For divisibility, memorize small rules: any number divisible by 3 if its digits sum to a multiple of 3; divisible by 4 if the last two digits form a multiple of 4. Saves tons of time on Data Sufficiency.
Use approximation when multiplying tricky numbers. For example, estimating 49 &times; 21 as (50 &times; 21) - 21 = 1050 - 21 = 1029 gives you a fast close answer.
For ratios, simplify early. If a question gives you a ratio like 12:18, reduce it immediately to 2:3 before plugging into further calculations.
Practice breaking large squares mentally. For example, 47&sup2; can be thought of as (50-3)&sup2; &rarr; 50&sup2; - 2&times;50&times;3 + 9 &rarr; 2500 - 300 + 9 = 2209.

Use quick checks to catch silly mistakes. After finishing, glance at whether your answer makes sense roughly &mdash; this prevents small calculation errors from killing accuracy.
For more details you can read this blog on " GMAT Arithmetic Tricks"

V Ritik · Answer

One thing that really helped me with GMAT Quant speed was tightening up my basic arithmetic. A few tricks made a big difference:
First, learn how to quickly break numbers into factors. For example, when dividing 180 by 12, mentally split 180 as 60 &times; 3 and divide step-by-step. This avoids long division and reduces errors.
Next, always simplify fractions before multiplying. If you&rsquo;re calculating (8/15) &times; (75/16), cancel out common factors first: 8 and 16, 15 and 75. It&rsquo;s much faster than multiplying across and then simplifying.
For percentages, memorize common shortcuts: 10% is just moving the decimal; 5% is half of 10%; 20% is double 10%. This avoids unnecessary calculations.
Finally, estimate when answer choices are spread far apart. If you can ballpark the answer quickly, you avoid wasting time on exact calculations.

B.K Sharma · Answer

One thing that really helped me with GMAT Quant speed was tightening up my basic arithmetic. A few tricks made a big difference:
First, learn how to quickly break numbers into factors. For example, when dividing 180 by 12, mentally split 180 as 60 &times; 3 and divide step-by-step. This avoids long division and reduces errors.
Next, always simplify fractions before multiplying. If you&rsquo;re calculating (8/15) &times; (75/16), cancel out common factors first: 8 and 16, 15 and 75. It&rsquo;s much faster than multiplying across and then simplifying.
For percentages, memorize common shortcuts: 10% is just moving the decimal; 5% is half of 10%; 20% is double 10%. This avoids unnecessary calculations.
Finally, estimate when answer choices are spread far apart. If you can ballpark the answer quickly, you avoid wasting time on exact calculations.

Mansih K · Answer

Sometimes the fastest way to solve a GMAT Quant problem is not to solve it at all&mdash;just test numbers smartly. For many word problems, especially in arithmetic, plugging in your own values works quicker than setting up equations.
Use these ideas: Pick easy numbers that match the condition. If a problem says "x is divisible by 5 and 7", try 35. For remainder questions, always test the smallest numbers first (like 1, 2, 3) to catch patterns. With percent changes, use a base value like 100 or 200&mdash;it makes gain/loss math way simpler.
Also, practice multiplying numbers like 25&times;4 or 15&times;6 quickly in your head&mdash;these come up often in rate and work questions. One more trick: memorize common fractions (like 1/8 = 12.5%) to avoid converting back and forth.
These habits shave seconds off every question&mdash;and that adds up.