Digital root technique

Digital root : Sum of digits till you get a single digit is known as digital root or sum.

For example digital root of 34567 Þ 3+4+5+6+7 = 25 Þ2+5 = 7    

Digital root (DR) of any mathematical calculations remains same from both the side

for example 123 (DR 6)+ 456 ( DR 6) = 579 ( DR 3)

In Similar manner DR technique can be used in multiplication also. The technique is useful only for exams when you have options so you can mathc DR of question or problem to DR of options to get correct option. Watch the video for further details.