Train your mental math & logic
Timed brain workouts. Build combos, earn points, and get faster one round at a time.
Start today's challenge 🚀🧮 Mental Math
View all →Addition & Subtraction Drills →
Work left to right: add the tens first, then the ones, then combine. For subtraction, it is usually faster to count up than to take away.
Multiplication Drills →
Break the second number into parts you already know, multiply each part, then add. Rounding to a nearby ten and correcting also works well.
Percentage Calculation →
Start from 10% — it is just the number with the decimal moved one place. Build every other percentage from 10%, 5% and 1% chunks.
Averages & Means →
The average is the total divided by the count. When numbers are close together, pick a base value and average only the differences from it.
Two-Digit Multiplication →
Keep the first number whole and split the second into its tens and ones. Multiply the whole number by each part, then add the two results.
Multiply by 11 Trick →
Multiplying by 11 is the same as multiplying by 10 and adding the number once more. For two-digit numbers you can also spread the digits and add the middle.
Squaring Two-Digit Numbers →
For a number ending in 5, multiply the tens digit by the next number up and stick 25 on the end. For others, round to a nearby ten and adjust.
Adding Large Numbers →
Add from the biggest place value down: thousands, then hundreds, then the rest. Keep one running total rather than stacking columns in your mind.
Tip & Bill Percentages →
Find 10% of the bill first, then scale it. A 20% tip is double the 10%; 15% is the 10% plus half of it again.
Fractions to Percentages →
Learn the handful of building blocks: 1/2 is 50%, 1/4 is 25%, 1/5 is 20%, 1/8 is 12.5%. Most fractions are just multiples of these.
✂️ Estimation
View all →Division Estimation →
Round the divisor to a clean number, divide, then nudge the answer. Keep only as many significant digits as the question actually needs.
Truncated Division →
Chop both the top and bottom to their first two or three significant digits, then divide. How many digits you keep depends on how close the options are.
Difference Method →
To compare two fractions, form a new fraction from the gaps between their tops and bottoms, then compare that with the smaller original.
Rounding to Estimate Products →
Round each number to the nearest ten, multiply the round numbers, and you have a fast ballpark. Track which way you rounded to judge if the real answer is a little higher or lower.
📊 Data Analysis
View all →Growth Rate Calculation →
Growth rate is the change divided by the starting value. You rarely need the exact figure — estimate the fraction and match it to the closest option.
Proportion & Share →
A share is the part divided by the total. To judge whether a share rose or fell, compare how fast the part grew against how fast the total grew.
Multiples (A ÷ B) →
A multiple is simply A divided by B. When the gap is large, truncate both numbers to their leading digits — that is usually precise enough.
🧩 Logic
View all →Number Sequences →
Look at the gaps between terms first. A constant gap means you add the same amount each time to reach the next number.
Geometric Sequences →
If the gaps keep growing, check for a constant ratio instead of a constant difference. Each term is the previous one multiplied by the same number.