709真题解说

=(709-302)×12,

=407×12,

=4884;

(2)98.3-3.32-5.68+11.7,

=(98.3+11.7)-(3.32+5.68),

=110-9,

=101;

(3)0.25×3.2×1.25,

=(0.25×4)×(0.8×1.25),

=1×1,

=1;

(4)13÷[(23+15)×113],

=13÷[1315×113],

=13÷115,

=13×15,

=5;

(5)(15-18)×5×8,

=15×5×8-18×5×8,

=8-5,

=3.