1011₂ + 10111₂
= (1000₂ + 10₂ + 1₂) + (10000₂ + 100₂ + 10₂ + 1₂)
= 10000₂ + 1000₂ + 100₂ + 2 (10₂) + 2 (1₂)
= 10000₂ + 1000₂ + 100₂ + 2 (10₂) + 10₂
= 10000₂ + 1000₂ + 100₂ + 100₂ + 10₂
= 10000₂ + 1000₂ + 2 (100₂) + 10₂
= 10000₂ + 1000₂ + 1000₂ + 10₂
= 10000₂ + 2 (1000₂) + 10₂
= 10000₂ + 10000₂ + 10₂
= 2 (10000₂) + 10₂
= 100000₂ + 10₂
= 100010₂