找窍门,怎样算简便就怎样算. (1)
(2)4-
(3)3
(4)[
(5)20
(6)
|
(1)
×5 6
-6 5
÷9 10 9 5
=1-
×9 10
,5 9
=1-
,1 2
=
;1 2
(2)4-
-5 11 7 11
=4-(
+5 11
),7 11
=4-1,
=3;
(3)3
×[(11 5
+2 3
)×21 5
]1 7
=
×[(16 5
+5 3
)×1 5
],15 7
=
×[16 5
×5 3
+15 7
×1 5
],15 7
=
×[16 5
+25 7
],3 7
=
×4,16 5
=12
;4 5
(4)[
-0÷(3 4
+1 7
)]×12 13 1 3
=[
-0]×3 4
,4 3
=
×3 4
,4 3
=1;
(5)20
×83+1.7×2001 100 1 10
=20.01×83+1.7×200.1
=200.1×8.3+1.7×200.1,
=(8.3+1.7)×200.1,
=10×200.1,
=2001;
(6)
÷[(4 5
-5 8
)÷1 2
]5 8
=
÷[(4 5
-5 8
)×1 2
],8 5
=
÷[4 5
×5 8
-8 5
×1 2
],8 5
=
÷[1-4 5
],4 5
=
÷4 5
,1 5
=4.