sir i want to ask for a book a computer book and problem solving book.please suggest me a good book for class 6.

@ swasti 
go for INFORMATION TACHNOLOGY books by educomp publication , its the best computer books ,and upto grade 10 , u have to know some besic things about computer , not many advanced thing , the advanced thing u wuill learn in class 11 th if u will take comp sci as a subject . 
and abt the problem solving , i think u are asking about the maths problem solving – then s,chand will be the suitable option for you . 
u can refer to the askiitian material and self study courses for that also . they will give u tricks on how to solve problems efficiently 
HOPE IT CLEARS YOUR DOUBT 
ALL THE BEST ..