| 2.5×0.125×32 | ×[1÷( - )] | ×67+ ×2+![]() | 9-1.72-3.28+5.5. |
=2.5×0.125×8×4,
=2.5×4×(0.125×8),
=10×1,
=10;
(2)
×[1÷(
-
)],=
×[1÷
],=
×[1×
],=
×
,=
;(3)
×67+
×2+
,=
×(67+2+1),=
×70,=16;
(4)9-1.72-3.28+5.5,
=9-(1.72+3.28)+5.5,
=9-5+5.5,
=4+5.5,
=9.5.
分析:(1)把32看作8×4,运用乘法交换律与结合律简算;
(2)先算小括号内的,再算中括号内的,最后算括号外的;
(3)运用乘法分配律简算;
(4)运用减法的性质简算.
点评:此题考查了小数、分数的错四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.