We can arrange the numbers in such a way that it becomes easy and quick to find the answer.
837 + 208 + 363 can be represented as :
= (837 + 363) + 208.
We club 837 and 363 as the last digits of numbers i.e 7 and 3 respectively adds up to 10. So the last digit of their sum will be 0.
By doing so, we get:
= 1200 + 208
= 1408