Ответ:

  1. \(4\frac{9}{25}+6.37=4.36+6.37=10.73\).
  2. \(12\frac{9}{40}-7.84=12.225-7.84=4.385\).
  3. \(\frac{7}{8}+3.23=0.875+3.23=4.105\).

Ответ: 1) 10,73; 2) 4,385; 3) 4,105.