Ответ:

  1. \(1\frac{1}{2}+2\frac{1}{2}=4\) — A.
  2. \(5\frac{3}{4}-2\frac{1}{4}=3\frac{2}{4}=3\frac{1}{2}\) — D.
  3. \(2\frac{1}{3}\cdot3=\frac{7}{3}\cdot3=7\) — E.
  4. \(3\frac{1}{5}+1\frac{2}{5}=4\frac{3}{5}\) — B.
  5. \(4\frac{2}{7}-1\frac{2}{7}=3\) — C.

Ответ: 1–А, 2–D, 3–E, 4–B, 5–C.