What is the divisibility test of 7?

Asked by Esha Singh | 10th Jul, 2014, 09:07: PM

Expert Answer:

S t e p space 1 : space O b s e r v e space t h e space f i n a l space d i g i t space o f space t h e space g i v e n space n u m b e r. space L e t space i t space b e space x S t e p space 2 : space D o u b l e space t h e space l a s t space d i g i t comma space l e t space i t space b e space 2 x S t e p space 3 : space S u b t r a c t space 2 x space f r o m space t h e space r e s t space o f space t h e space g i v e n space n u m b e r. S t e p space 4 : space I f space t h e space r e m a i n d e r space i s space e x a c t l y space d i v i s i b l e space b y space 7 comma space t h e n space t h e space g i v e n space n u m b e r space i s space a l s o space d i v i s i b l e space b y space 7. space A n d space space space space space space space space space space space space space i f space t h e space r e m a i n d e r space i s space n o t space d i v i s i b l e space b y space 7 comma space t h e n space t h e space g i v e n space n u m b e r space i s space a l s o space n o t space d i v i s i b l e space b y space 7. E x a m p l e : space C o n s i d e r space t h e space d i v i s i b l i t y space c h e c k space o f space 371 space b y space t h e space n u m b e r space 7 B y space s t e p space 1 : space L e t space x equals 1 B y space s t e p space 2 : space L e t space 2 x equals 2 B y space s t e p space 3 : space S u b t r a c t space 2 space f r o m space 37 comma space t o space g e t space 35 B y space s t e p space 4 : space 35 space i s space e x a c t l y space d i v i s i b l e space b y space 7 space a n d space h e n c e space t h e space g i v e n space n u m b e r space i s space d i v i s i b l e space b y space 7. E x a m p l e : space C o n s i d e r space t h e space d i v i s i b l i t y space c h e c k space o f space 583 space b y space t h e space n u m b e r space 7 B y space s t e p space 1 : space L e t space x equals 3 B y space s t e p space 2 : space L e t space 2 x equals 6 B y space s t e p space 3 : space S u b t r a c t space 6 space f r o m space 58 comma space t o space g e t space 52 B y space s t e p space 4 : space 52 space i s space n o t space e x a c t l y space d i v i s i b l e space b y space 7 space a n d space h e n c e space t h e space g i v e n space n u m b e r space i s space n o t space d i v i s i b l e space b y space 7.

Answered by Vimala Ramamurthy | 11th Jul, 2014, 10:06: AM