脱式计算. 457-(69+72×4) (360÷12)×(120-84) 6.1-(2.2-0.25) (974-94×5)÷36 760÷40-(12.7+5.63) 25×[180÷(15×4)]
第1个回答 2019-03-31
(1)457-(69+72×4)
=457-(69+288)
=457-357
=100;
(2)(360÷12)×(120-84)
=30×36
=1080;
(3)6.1-(2.2-0.25)
=6.1-1.95
=4.15;
(4)(974-94×5)÷36
=(974-470)÷36
=504÷36
=14;
(5)760÷40-(12.7+5.63)
=760÷40-18.33
=19-18.33
=0.67;
(6)25×[180÷(15×4)]
=25×[180÷60]
=25×3
=75.
=457-(69+288)
=457-357
=100;
(2)(360÷12)×(120-84)
=30×36
=1080;
(3)6.1-(2.2-0.25)
=6.1-1.95
=4.15;
(4)(974-94×5)÷36
=(974-470)÷36
=504÷36
=14;
(5)760÷40-(12.7+5.63)
=760÷40-18.33
=19-18.33
=0.67;
(6)25×[180÷(15×4)]
=25×[180÷60]
=25×3
=75.