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Thursday 31 January 2013

Maths Tricks with Numbers

Maths Tricks with Numbers

Trick 1:Quick Square

  1. If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. 
  2. Mulitply the first digit by itself + 1, and put 25 on the end. 
  3. That is all!
  4. Ex:25 ie(2*(2+1))&25
Answer:625

Trick 2: Multiply by 5

  1. Take any number, then divide it by 2
  2. If the result is whole, add a 0 at the end.
  3. If it is not, ignore the remainder and add a 5 at the end. 
  4. 2682 x 5 = (2682 / 2) & 5 or 0
  5. 2682 / 2 = 1341 (whole number so add 0)
  6. Ans:13410
  7. Let’s try another:5887 x 5,2943.5 (fractional numbers (ignore remainder, add 5)
Answer: 29435

Trick 3: Tough Multiplication

  1. If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer
  2. Ex:32 x 125, is the same as: 16 x 250 is the same as: 8 x 500 is the same as: 4 x 1000 = 4,000

Trick 4: Subtracting from 1,000

  1. To subtract a large number from 1,000 you can use this basic rule: subtract all but the last number from 9, then subtract the last number from 10:
  2. Ex:1000-648
  3. subtract 6 from 9 = 3
  4. subtract 4 from 9 = 5
  5. subtract 8 from 10 = 2 
Answer: 352

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