A TRICK TO CHECK DIVISIBILITY BY 7

There are many tricks in mathematics to solve a problem quickly and easily!

Question:  Can you divide 406 by 7 without leaving a remainder?

This is the trick

• Take the last digit of the number
• Double it
• Subtract the number thus obtained from the given number without the last digit
• If you can divide the number obtained by 7, you can divide the given number also by 7

Here, the given number is 406

• Take the last digit. It is 6
• Double it; we get 12
• Subtract 12 from 40; we get 28
• 28 is divisible by 7. So 406 is also divisible by 7.

Now try the following questions.

Which of the following numbers are divisible by 7?
 (a)  441      (b) 623    (c) 474    (d) 4886    (e)  6249      (f)  444724  (g) 75328

Wait for the next post to be published soon to learn about the trick to check divisibility by 7 of a number having 4 or more digits.
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