1) 3,72+2,97+1,03+1,28=(3,72+1,28)+(2,97+1,03)=5+4=9;
2) (12,548+4,242)−2,548=(12,548−2,548)+4,242=10+4,242=
=14,242;
3) 9,113−(2,113+4,8)=(9,113−2,113)−4,8=7−4,8=2,2;
4) 12,5⋅1,9⋅0,08=(12,5⋅0,08)⋅1,9=1⋅1,9=1,9;
5) 9,7⋅7,4+9,7⋅1,6=9,7⋅(7,4+1,6)=9,7⋅9=87,3;
6) 4,42⋅5,7−2,7⋅4,42=4,42⋅(5,7−2,7)=4,42⋅3=13,26.