| 3.1+2.4+1.9+3.6 | 300-288÷24 | 48×( + ) | 0.46×98+0.92 |
× ÷ ×![]() | 21÷( + )÷ . |
=(3.1+1.9)+(2.4+3.6),
=5+6,
=11;
(2)300-288÷24,
=300-12,
=288;
(3)48×(
+
),=48×
+48×
,=18+40,
=58;
(4)0.46×98+0.92,
=0.46×(100-2)+0.92,
=0.46×100-0.46×2+0.92,
=46-0.92+0.92,
=46;
(5)
×
÷
×
,=(

)×(
),=1×0.16,
=0.16;
(6)21÷(
+
)÷
,=21÷
,=21÷(
),=21
,=35.
分析:(1)运用加法交换律和结合律解答,
(2)依据四则运算的运算顺序解答,
(3)、(4)运用乘法分配律解答,
(5)运用乘法交换律解答,
(6)依据除法性质解答.
点评:本题主要考查四则混合运算的运算顺序以及运用运算定律简算的能力.