| 62.8×19-8×62-62 | 3.64×[1÷(2-2.09)] |
| 1.9-1.9×(1.9-1.9) | (1-1%×70)÷0.32O |
=1193.2-496-62,
=635.2;
(2)3.64×[1÷(2-2.09)]
=3.64×[1÷(-0.09)],
=
×(-
),=-
;(3)1.9-1.9×(1.9-1.9)
=1.9-1.9×0,
=1.9-0,
=1.9;
(3)(1-1%×70)÷0.32O
=(1-0.7)÷
,=
×
,=
.分析:本题根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
点评:在完成算式(2)时要注意2-2.09不够减,可先算2.09-2,然后在得数前加上“-”,正数除以或乘一个负数,还得负数.