Ответ:

  1. 15 = 8 + 4 + 2 + 1 = 23 + 22 + 21 + 20 = 11112.
  2. 32 = 25 = 1000002.
  3. 47 = 32 + 8 + 4 + 2 + 1 = 1011112.
  4. 99 = 64 + 32 + 2 + 1 = 11000112.

Ответ: 1) 15₁₀ = 1111₂; 2) 32₁₀ = 100000₂; 3) 47₁₀ = 101111₂; 4) 99₁₀ = 1100011₂.