Prime 59 is a number puzzle game where you fill a 6×6 grid using only prime numbers so that every row and column adds up to exactly 59.

What are prime numbers?

Prime numbers are numbers greater than 1 that can only be divided evenly by 1 and themselves. Examples include 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, and 31.

Is Prime 59 free to play?

Yes! Prime 59 is free to download and play. A premium subscription unlocks additional features like advanced stats, unlimited daily challenges, and ad-free gameplay.

Is there multiplayer?

Yes! Battle Mode lets you challenge friends with a direct link or get matched with players worldwide. Both players solve the same puzzle in real-time.

What platforms is Prime 59 available on?

Prime 59 is available on iOS (App Store), Android (Google Play), and the web at prime59.fun. Your account syncs across all platforms.

Easy Mental Math Tricks to Do in Your Head

Mental math is a valuable skill that helps you make quick calculations without reaching for a calculator. Whether you’re shopping, splitting a bill, or solving a puzzle, mastering a few easy tricks can make everyday math much smoother. Let’s explore practical techniques you can start using right away.

Speedy Addition and Subtraction

Round and Adjust: To add 48 + 36, round 48 to 50 (add 2), then add 36 (50 + 36 = 86), then subtract the 2 you added (86 - 2 = 84).
Break Apart Numbers: For 27 + 46, split 27 into 20 and 7. Add 20 + 46 = 66, then add 7 for a total of 73.
Subtract in Steps: For 72 - 39, subtract 40 (72 - 40 = 32), then add back 1 (32 + 1 = 33).

Multiplication Shortcuts

Multiply by 9: To find 9 × 7, think (10 × 7) - 7 = 70 - 7 = 63.
Double and Halve: For 14 × 15, halve one and double the other: 7 × 30 = 210.
Use Nearby Numbers: For 13 × 12, calculate 12 × 12 = 144, then add another 12 (156).

Squares and Estimation

Square Numbers Ending in 5: For 35², multiply 3 (the first digit) by 4 (next higher number): 3 × 4 = 12; then put 25 at the end: 1225.
Estimate with Friendly Numbers: When multiplying 49 × 21, round 49 to 50 (50 × 21 = 1050), then subtract 21 (1050 - 21 = 1029).

Practice Makes Perfect

Regular practice is the key to getting faster and more confident with mental math. Number games can make this fun and engaging. For example, Prime 59 is a number-logic puzzle where you fill a 6×6 grid with prime numbers so every row and column sums to 59. This daily challenge sharpens your arithmetic skills and reinforces mental calculation techniques, especially with addition and prime recognition.

Tips for Improving Mental Math

Start with small numbers and gradually increase difficulty.
Visualize numbers on a number line or in groups.
Challenge yourself with puzzles and games that require quick calculations.
Practice regularly to build speed and accuracy.

With these tricks and consistent practice, you’ll find mental math becoming second nature—making everyday calculations faster and more reliable.