Multiplying by 11 (Fast)

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Multiplying by 11 (Fast)Let’s say we need to multiply 3874 × 11 Now, to do this, we make 11 = 10 + 1 3874 × 11 = 3874 × (10 + 1) = 38740 + 3874 Putting 38740 and 3874 below each other to add So, for 3874 × 11, we do these steps Step 1: The Right End. Copy the last digit down. The last digit is 4. Write 4. (Current Answer: _ _ _ _ 4) Step 2: Add Neighbors (moving left). Add the last digit (4) to its neighbor (7). 4 + 7 = 11. Write down 1 and carry over the 1. (Current Answer: _ _ _ 1 4) Step 3: Keep Moving Left. Add the next neighbors: 7 + 8. 7 + 8 = 15. Add the carry (1) = 16. Write down 6 and carry over the 1. (Current Answer: _ _ 6 1 4) Step 4: Keep Moving Left. Add the next neighbors: 8 + 3. 8 + 3 = 11. Add the carry (1) = 12. Write down 2 and carry over the 1. (Current Answer: _ 2 6 1 4) Step 5: The Left End. Take the first digit (3). Add the carry (1). 3 + 1 = 4. Thus, final answer is 42614 Let’s do some questions Find (b) 5678 × 11 We follow these steps Step 1: The Right End. Copy the last digit down. The last digit is 8. Write 8. (Current Answer: _ _ _ _ 8) Step 2: Add Neighbors (moving left). Add the last digit (8) to its neighbor (7). 8 + 7 = 15. Write down 5 and carry over the 1. (Current Answer: _ _ _ 58) Step 3: Keep Moving Left. Add the next neighbors: 7 + 6. 7 + 6 = 13. Add the carry (1) = 14. Write down 4 and carry over the 1. (Current Answer: _ _ 458) Step 4: Keep Moving Left. Add the next neighbors: 5 + 6. 5 + 6 = 11. Add the carry (1) = 12. Write down 2 and carry over the 1. (Current Answer: _ 2458) Step 5: The Left End. Take the first digit (5). Add the carry (1). 5 + 1 = 6. Thus, final answer is 62458