Multiplying Whole Numbers Close to Each Other

These multiplication tricks will only work for you if you have memorized or can quickly calculate the square of numbers. Learn the trick of finding square of any two digit number.  Also master the shortcut to find the square of any number.

Multiplication of Two Numbers that Differ by 2

When two numbers differ by 2, their product is always the square of the number in between these numbers minus 1.

Example
1. 18*20 = 19^2 – 1 = 361 – 1 = 360
2. 25*27 = 26^2 – 1 = 676 – 1 = 675
3. 49*51 = 50^2 – 1 = 2500 – 1 = 2499

Multiplication of Two Numbers that Differ by 4

If two numbers differ by 4, then their product is the square of the number in the middle (the average of the two numbers) minus 4.

Example
1. 22*26 = 24^2 – 4 = 572
2. 98*102 = 100^2 – 4 = 9996

3. 148*152 = 150^2 – 4 = 22496

 

Multiplication of Two Numbers that Differ by 6

If the two numbers differ by 6 then their product is the square of their average minus 9.

Example

1. 10*16 = 13^2 – 9 = 160
2. 22*28 = 25^2 – 9 = 616

3. 997*1003 = 1000^2 – 9 = 999991

 

Now come with numbers with any of the conditions mentioned above and try solving them using these multiplication tricks. By practice you will be able to master these multiplication shortcuts.

Let me know if the above trick helped you in any way. Waiting for your feedback.

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Vineet Patawari

Hi, I'm Vineet Patawari. I fell in love with numbers after being scared of them for quite some time. Now, I'm here to make you feel comfortable with numbers and help you get rid of Math Phobia!

8 thoughts to “Multiplying Whole Numbers Close to Each Other”

  1. Multiplication of Two Numbers that Differ by 8

    If the two numbers differ by 8 then their product is the square of their average minus 16.

    Example

    1. 10*18 = 14^2 – 16 = 180
    2. 22*30 = 26^2 – 16 = 660

    3. 990*998 = 994^2 – 16 = 988036

    thanks for your tricks sir 🙂

  2. A REDUCTION OF 20% IN THE PRICE OF A PEN ENABLES A CUSTOMER TO PURCHASE 12 MORE PENS FOR RUPEES 15 . WHAT IS THE ORIGNAL PRICE OF 16 PENS BEFORE REDUCTION ? .

    1. If x = price of pen and y = no. of pens. Hence xy = 15, then

      0.8x*(y+12) = 15
      or, 0.8xy + 9.6x = 15
      0r, x = (15 – 0.8*15)*10/96
      0r, 16x = 3*10*16/96
      or, 16x = 5

      Answer: Original price of 16 pens = Rs. 5

  3. Great ideas and helpful tricks not only to solve not only the above mentioned multiplication problems, but also to keep the mind young and sharp by using these mental calculation strategies. Thanks a lot for your efforts.

  4. Great ideas and helpful tricks not only to solve not only the above mentioned multiplication problems, but also to keep the mind young and sharp by using these mental calculation strategies. Thanks a lor for your efforts

  5. Awesome trick! i really was looking forward to such tricks! Hopefully your website ends my search 🙂 Keep posting such awesome tricks! Love them:)

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