a) \(571 + 216 + 129 + 124\)

\(= \left(\right. 571 + 129 \left.\right) + \left(\right. 216 + 124 \left.\right)\)

\(= 700 + 340\)

\(= 1 040.\)

b) \(27.74 + 26.27 - 355\)

\(= 27. \left(\right. 74 + 27 \left.\right) - 355\)

\(= 27.100 - 355\)

\(= 2700 - 355\)

\(= 2 345.\)

c)  100:{250:[450−(4.53−22.25)]}

\(= 100 : \left{\right. 250 : \left[\right. 450 - \left(\right. 4.125 - 4.25 \left.\right) \left]\right. \left.\right}\)

\(= 100 : \left[\right. 250 : \left(\right. 450 - 400 \left.\right) \left]\right.\)

\(= 100 : \left(\right. 250 : 50 \left.\right)\)

\(= 100 : 5 = 20.\)

a)320;4914;90

b)320;90;2315

c)4914

d)4914