Page 43 - magazine 1 august

Mathematics Corner

Divisibility Test Rule

We all know the DIVISIBILITY rules of 2,3,4,5,6,8,9 and 11. But it becomes difficult to
check the DIVISIBILITY of 7,13,17 and 19. Here are some simple steps to check the
DIVISIBILITY of above numbers.

To check the divisibility of a number by 7,13,17 and 19 select N and L . Here L is
last digit of the number and N is the rest of the number.

Divisibility by 7 :- If N-2L is divisible by 7 then the number is also
divisible by 7 .

Divisibility by 13 :- If N+4L is divisible by 13 then the number is
also divisible by 13.

Divisibility by 17 :- If N- 5L is divisible by 17 then the number Sulkshna
is also divisible by 17. TGT (Mathematics)
RPVV SEC -21 Rohini
Divisibility by 19:- If N+ 2L is divisible by 19 then the number is
also divisible by 19.

Note :- You can repeat the process till you get the easy answer .
Example:- in 7684 L=4, N=768

Divisibility Div. by 7 Div. by 13 DIV. by 17 Div. by 19
by
Rule N-2L N+4L N-5L N+2L

Step -1 768-2x4 768+4x4= 768-5x4 768 +2x4
=760 784 =748 =760

Step-2 76-2x0=76 76+4x4=92 74 - 5x8 = 34 76+ 2x0= 76
Step-3 76 is not 92 is not div 34 is div. By 76 is div by
div. By 7 by 13 17 19
Step-4 7684 is not 7684 is not 7684 is div. 7684 is div
div by 7 div by 13 By 17 by 19

Now practice these rules with some more numbers and enjoy the fun of

maths with your friends.