Data Sufficiency

A, b and c are 3 digit positive integers, where a=b+c. Is the hundreds digit of A equal to the sum of the hundreds digit of b and the hundreds digit of c?
(1) the tens digit of A is equal to the sum of the tens digit of b and the tens digit of c
(2) the units digit of a is equal to the sum of the units digit of b and the units digit of c.

Answer is A.

From1 we know the sum of tens digits of B and C is equal to tens digit of A.
What this means is that there is carry over from the sum of tenses digit of B and C. You can pick a few examples to see that the Sum of hundreds digit of B and C will be equal to the hundreds digit of A. So this is sufficent

From 2 all we know is that the units digits don't have carry over to the tens digits. But we can provide two examples where
1. There is a carry over form tens digits sum to hundreds digits
A = B + C
235 = 125 + 110
In this case answer is Yes sum of hundreds digits of B and C is equal to
Hundreds digit of A
2. There is a carry over from tens digits sum
A = B + C
305 = 195 + 110
In this case answer is No
Therefore 2 is Insufficient.

What is the OA