Answer:
1000
Step-by-step explanation:
11=1×2^1+1×2^0
101=1×2^2+0×2^1+1×2^0
Adding 2^0 's together gives 2×2^0. As two is not an allowed digit in binary, we must rewrite as 1×2^1 and carry over.
Combining 2^1 terms gives 2×2^1. We run into same problem. We will rewrite as 1×2^2 and carry.
Combining 2^2 terms gives 2×2^2. Same problem... we rewrite as 1×2^3 and carry.
No more 2^3 's other than the one we carried over from previous addition.
Answer is 1000.
Another way.
Covert fully to base 10 and then add. Then convert back.
11=1×2^1+1×2^0=2+1=3.
101=1×2^2+0×2^1+1×2^0=5.
3+5=8
2^3=8...which means there are no 2^2 's, 2^1 's, or 2^0 's.
