题目内容
脱式计算.(能简算的要简算)
(1)1990×1999-1989×2000
(2)
÷[(
+
)×
]
(3)
(4)4-[3.75×(1.2-
)+
].
(1)1990×1999-1989×2000
(2)
| 4 |
| 25 |
| 2 |
| 5 |
| 1 |
| 3 |
| 9 |
| 11 |
(3)
| 567+345×566 |
| 567×345+222 |
(4)4-[3.75×(1.2-
| 1 |
| 3 |
| 3 |
| 4 |
(1)1990×1999-1989×2000
=1990×1999-1989×1999-1989
=1999×-1989
=1999-1989
=10
(2)
÷[(
+
)×
]
=
÷[
×
]
=
×
=
(3)
=
=
=1
(4)4-[3.75×(1.2-
)+
]
=4-[
×
+
]
=4-4
=0
=1990×1999-1989×1999-1989
=1999×-1989
=1999-1989
=10
(2)
| 4 |
| 25 |
| 2 |
| 5 |
| 1 |
| 3 |
| 9 |
| 11 |
=
| 4 |
| 25 |
| 11 |
| 15 |
| 9 |
| 11 |
=
| 4 |
| 25 |
| 5 |
| 3 |
=
| 4 |
| 15 |
(3)
| 567+345×566 |
| 567×345+222 |
=
| 345+345×566+222 |
| 567×345+222 |
=
| 567×345+222 |
| 567×345+222 |
=1
(4)4-[3.75×(1.2-
| 1 |
| 3 |
| 3 |
| 4 |
=4-[
| 15 |
| 4 |
| 13 |
| 15 |
| 3 |
| 4 |
=4-4
=0
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