题目内容
脱式计算(能简便计算的要简便计算).
÷
+
×
÷[1-(
+
)]
1.25×(0.8+8+80)
| 4 |
| 7 |
| 11 |
| 5 |
| 3 |
| 7 |
| 5 |
| 11 |
| 5 |
| 6 |
| 3 |
| 4 |
| 1 |
| 16 |
1.25×(0.8+8+80)
分析:(1)把除法变为乘法,运用乘法分配律简算;
(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.
(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.
解答:解:(1)
÷
+
×
=
×
+
×
=(
+
)×
=1×
=
;
(2)
÷[1-(
+
)]
=
÷[1-
]
=
÷
=
×
=
;
(3)1.25×(0.8+8+80)
=1.25×0.8+1.25×8+1.25×80
=1+10+100
=111.
| 4 |
| 7 |
| 11 |
| 5 |
| 3 |
| 7 |
| 5 |
| 11 |
=
| 4 |
| 7 |
| 5 |
| 11 |
| 3 |
| 7 |
| 5 |
| 11 |
=(
| 4 |
| 7 |
| 3 |
| 7 |
| 5 |
| 11 |
=1×
| 5 |
| 11 |
=
| 5 |
| 11 |
(2)
| 5 |
| 6 |
| 3 |
| 4 |
| 1 |
| 16 |
=
| 5 |
| 6 |
| 13 |
| 16 |
=
| 5 |
| 6 |
| 3 |
| 16 |
=
| 5 |
| 6 |
| 16 |
| 3 |
=
| 40 |
| 9 |
(3)1.25×(0.8+8+80)
=1.25×0.8+1.25×8+1.25×80
=1+10+100
=111.
点评:考查了小数、分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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