Singh Tricks

How to multiply any two digits number by 11 Let’s say that you want to find the product of 36 and 11. One way to find it would be to multiply 36 by 10 and then add 36 on the result. There is, however, a simple trick that’ll do the job for any two digits number. To find out the result, write the first digit followed by the addition of the first and second digit, followed by the second digit. For example 36*11 now, 3(3+6)6=396 Example: What happens if the sum of the two numbers is bigger than 9? In this case you add 1 to the first number, followed by the last digit of the addition of the two numbers, and then again you add the second number For example 87*11 now, 8(8+7)7=957

Square any two digits number that ends with 5 Calculating the square of a number below 100 is extremely simple. If you wantto find the square of 25 for example, you simply have to take the first digit (2), multiply it for the next highernumber (3), and then add 25 to the result. For example 1). 25*25 now, (2*3)25=625 2). 75*75 now, (7*8)25=5625

Multiplying by 11 is easier when adjusting the rule for multiplying by 9. Just think of11 as (10+1) So 436 × 11 = 4360 + 436 = 4796…that’s the simpler way of explaining why the digits add up to each other like youwrote: 4360 + 436 —– 4796

How to multiply any two digits number by 11 Let’s say that you want to find the product of 36 and 11. One way to find it would be to multiply 36 by 10 and then add 36 on the result. There is, however, a simple trick that’ll do the job for any two digits number. To find out the result, write the first digit followed by the addition of the first and second digit, followed by the second digit. Example: What happens if the sum of the two numbers is bigger than 9? In this case you add 1 to the first number, followed by the last digit of the addition of the two numbers, and then again youadd the second number

Multiplying by 11 is easier when adjusting the rule for multiplying by 9. Just think of11 as (10+1) So 436 × 11 = 4360 + 436 = 4796…that’s the simpler way of explaining why the digits add up to each other like youwrote: 4360 + 436 —– 4796

Link to previous multiplication post 7. Squaring other 2-digit numbers Let’s say you want to square58. Square each digit and write a partial answer. 5×5 = 25. 8×8 = 64. Write down 2564 to start. Then, multiply the two digits of the number you’re squaring together, 5×8=40. Double this product: 40×2=80, then add a 0 to it, getting 800. Add 800 to 2564 to get 3364. This is pretty complicated so let’s do more examples. 32×32. The first part of the answer comes from squaring 3 and 2. 3×3=9. 2×2 = 4. Write down 0904. Notice the extra zeros.It’s important that every square in the partial product have two digits. Multiply the digits, 2 and 3, together and double the whole thing. 2×3x2 = 12. Add a zero to get 120. Add 120 to the partial product, 0904, and we get 1024. 56×56. The partial product comes from 5×5 and 6×6. Write down 2536. 5×6x2 = 60. Add a zero to get 600. 56×56 = 2536+600 = 3136. One more example: 67×67. Write down 3649 as the partial product. 6×7x2 = 42×2 = 84. Add

1. Multiplying by 9, or 99, or 999 Multiplying by 9 is really multiplying by 10-1. So, 9×9 is just 9x(10-1) which is 9×10-9 which is 90-9 or 81. Let’s try a harder example: 46×9 = 46×10-46 = 460-46 =414. One more example: 68×9 = 680-68 = 612. To multiply by 99, you multiply by 100-1. So, 46×99 = 46x(100-1) = 4600-46 = 4554. Multiplying by 999 is similar to multiplying by 9 and by 99. 38×999 = 38x(1000-1) = 38000-38 = 37962. 2. Multiplying by 11 To multiply a number by 11 you add pairs of numbers next to each other, except for the numbers on the edges. Let me illustrate: To multiply 436 by 11 go fromright to left. First write down the 6 then add 6 to its neighbor on the left, 3, to get 9. Write down 9 to the left of 6. Then add 4 to 3 to get 7. Write down 7. Then, write down the leftmostdigit, 4. So, 436×11 = is 4796. Let’s do another example: 3254×11. The answer comes from these sums and edge numbers: (3)(3+2)(2+5)(5+4)(4) = 35794. One more example, this one involvi