题目内容
| 计算下列各题,能简便都尽量简便. (1)(
| (2)[1-(
| ||||||||||
| (3)3.75×4.8+62.5×0.48 | (4)
| ||||||||||
| (5)1991+199.1+19.91+1.991 | (6)
|
(1)(
-
)÷
,
=(
-
)×
,
=
×
-
×
,
=
-
,
=
;
(2)[1-(
-
)]÷13,
=[1-
]÷13,
=
÷13,
=
;
(3)3.75×4.8+62.5×0.48,
=3.75×4.8+6.25×4.8,
=(3.75+6.25)×4.8,
=10×4.8,
=48;
(4)
÷(
+
),
=
÷
,
=
;
(5)1991+199.1+19.91+1.991,
=(2000-9)+(200-0.9)+(20-0.09)+(2-0.009),
=(2000+200+20+2)-(9+0.9+0.09+0.009),
=2222-9.999,
=2222-(10-0.001),
=2222-10+0.001,
=2212.001;
(6)
×37,
=(1-
)×37,
=1×37-
×37,
=37-
,
=36
.
| 3 |
| 4 |
| 1 |
| 8 |
| 5 |
| 12 |
=(
| 3 |
| 4 |
| 1 |
| 8 |
| 12 |
| 5 |
=
| 3 |
| 4 |
| 12 |
| 5 |
| 1 |
| 8 |
| 12 |
| 5 |
=
| 9 |
| 5 |
| 3 |
| 10 |
=
| 3 |
| 2 |
(2)[1-(
| 3 |
| 5 |
| 1 |
| 4 |
=[1-
| 7 |
| 20 |
=
| 13 |
| 20 |
=
| 1 |
| 20 |
(3)3.75×4.8+62.5×0.48,
=3.75×4.8+6.25×4.8,
=(3.75+6.25)×4.8,
=10×4.8,
=48;
(4)
| 4 |
| 15 |
| 4 |
| 7 |
| 4 |
| 8 |
=
| 4 |
| 15 |
| 15 |
| 14 |
=
| 56 |
| 225 |
(5)1991+199.1+19.91+1.991,
=(2000-9)+(200-0.9)+(20-0.09)+(2-0.009),
=(2000+200+20+2)-(9+0.9+0.09+0.009),
=2222-9.999,
=2222-(10-0.001),
=2222-10+0.001,
=2212.001;
(6)
| 44 |
| 45 |
=(1-
| 1 |
| 45 |
=1×37-
| 1 |
| 45 |
=37-
| 37 |
| 45 |
=36
| 8 |
| 45 |
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