Ответ:

  1. \(10\cdot2:0.4-2.6\cdot(-3)=20:0.4+7.8=50+7.8=57.8\).
  2. \(4.5+5^2\cdot0.4-10^3\cdot0.006=4.5+25\cdot0.4-6=4.5+10-6=8.5\).
  3. \(10^2\cdot0.63-5^2\cdot0.008+4.44=63-0.2+4.44=67.24\).
  4. \(6.8-25^2\cdot0.4-10^3\cdot0.045=6.8-625\cdot0.4-45=6.8-250-45=-288.2\).