Ответ:

  1. \[\frac{83.4+84.5}{2}=\frac{167.9}{2}=83.95.\]

  2. \[\frac{0.2+0.3+0.4}{3}=\frac{0.9}{3}=0.3.\]

  3. \[\frac{2.23+2.26+2.34+2.07}{4}=\frac{8.90}{4}=2.225.\]

  4. \[\frac{6.276+5.864+7.223+9.106+8.728+3.003}{6}=\frac{40.2}{6}=6.7.\]

Ответ: а) 83,95; б) 0,3; в) 2,225; г) 6,7.