Multiplication Trick: Multiply Any Number by 11

Multiplication Trick: Multiply Any Number by 11

Multiplication Trick: Multiply Any Number by 11

Multiplying by 11 is a powerful mental math trick that helps you solve calculations quickly, making it especially useful for competitive exams, school tests, and everyday calculations. Instead of using traditional multiplication methods, you can learn quick mental shortcuts to multiply any number by 11 within seconds.

This article will break down the step-by-step process and provide solved examples, practice exercises, and visual aids to help you master this technique effortlessly.

Why Learn the 11 Multiplication Trick?

  • Saves Time – No need for lengthy calculations or writing down steps.
  • Boosts Accuracy – Reduces the chances of making calculation errors.
  • Useful for Exams – Helps in competitive exams like CAT, GRE, GMAT, and SAT.
  • Fun to Learn – Makes mental math engaging and practical.

Multiplication with 11 – The Simple Trick

Case 1: Multiplying a Two-Digit Number by 11

For any two-digit number (AB) multiplied by 11, follow these steps:

  1. Separate the digits – Write the first and last digit as they are.
  2. Find the middle digit – Add the two digits together and place the sum in between.

Example 1: 42 × 11

  • Step 1: Separate the digits → 4 _ 2
  • Step 2: Add the digits (4 + 2) → 6
  • Step 3: Insert the sum in between → 462

So, 42 × 11 = 462

Example 2: 57 × 11

  • Step 1: Separate the digits → 5 _ 7
  • Step 2: Add the digits (5 + 7) → 12
  • Step 3: Place 2 in the middle and carry over 1 to the first digit.
    • New number: (5+1) 2 7 = 627

So, 57 × 11 = 627

Case 2: Multiplying a Three-Digit Number by 11

For a three-digit number (ABC):

  1. Write the first and last digit as they are.
  2. Find the middle digits by adding each consecutive pair of digits.
  3. If any sum is greater than 9, carry over to the previous digit.

Example 3: 314 × 11

  • Step 1: Separate digits → 3 _ _ 4
  • Step 2: Add consecutive pairs:
    • 3 + 1 = 4
    • 1 + 4 = 5
  • Step 3: Insert the sums → 3454

So, 314 × 11 = 3454

Case 3: Multiplying Larger Numbers by 11

For four-digit numbers and beyond, repeat the same process:

Example 4: 1,236 × 11

  1. Write the first and last digit as they are: 1 _ _ _ 6
  2. Add consecutive digits:
    • 1 + 2 = 3
    • 2 + 3 = 5
    • 3 + 6 = 9
  3. Insert the sums → 13,596

So, 1,236 × 11 = 13,596

Shortcut Recap: Multiply Any Number by 11 Instantly

  • For two-digit numbers: Write the sum of digits in the middle.
  • For three-digit numbers: Add consecutive pairs and place the sums between the original digits.
  • For four-digit numbers and beyond: Keep adding adjacent digits and inserting the sums in order.

Practice Exercises

Try these on your own using the trick:

  1. 36 × 11 = ?
  2. 68 × 11 = ?
  3. 152 × 11 = ?
  4. 417 × 11 = ?
  5. 5,432 × 11 = ?

Real-Life Applications of This Trick

  • Shopping calculations: Quickly estimate discounts and prices.
  • Banking and finance: Useful for interest rate calculations.
  • Competitive exams: Save time in quantitative aptitude sections.
  • Daily life: Mental math skills help in faster decision-making.

Final Thoughts

Multiplying by 11 is an easy yet powerful mental math trick that can significantly speed up calculations. Whether you’re preparing for an exam or just want to sharpen your arithmetic skills, mastering this method will give you a competitive edge.

Multiplication Trick: Multiply Any Number by 11