(1)2.9+6.46+7.1+3.54,
=(2.9+7.1)+(6.46+3.54),
=10+10,
=20;
(2)2.3÷8÷12.5,
=2.3÷(8×12.5),
=2.3÷100,
=0.023;
(3)0.4×(25+2.5),
=0.4×25+0.4×2.5,
=10+1,
=11;
(4)4.95×[2.46÷(5.58-5.28)],
=4.95×[2.46÷0.3],
=4.95×8.2,
=40.59;
(5)9.16-1.25-3.16-2.75,
=9.16-3.16-1.25-2.75,
=(9.16-3.16)-(1.25+2.75),
=6-4,
=2.