did not get logic behind this answer , why we subtract remainder from 9999
Question 6 : Find the largest four digit number exactly divisible by 15,21 and 28.
Solution : The largest four digit number is 9999.
Now, LCM (15, 21, 28) = 420
On dividing 9999 by 420, we get 339 as the remainder.
Therefore, the required number is 9999-339 = 9660