计算 ①5.2×1
②2
③[3.75-(
④
⑤(7
⑥
⑦(
⑧1
|
①5.2×1
+21 4
÷4 5 4 5
=5.2×
+2.8×5 4
,5 4
=(5.2+2.8)×
,5 4
=8×
,5 4
=10;
②2
-(5 8
+2 3
+1 4
),5 6
=2
-(5 8
+8 12
+3 12
)10 12
=2
-15 8
,3 4
=
;7 8
③[3.75-(
+1 5
)×41 3
]÷1 2
,3 5
=[3.75-
×8 15
]÷9 2 3 5
=[3.75-2.4]÷0.6,
=1.35÷0.6,
=2.25;
④
÷(0.6×1.25+11 4
+1 8
),1 4
=
÷(1 4
×3 5
+15 4
+1 8
),1 4
=
÷(1 4
+3 4
+11 4
)1 8
=
×1 4
,8 17
=
;2 17
⑤(7
×2+71 3
+71 3
)÷4,1 3
=7
×(2+1+1)÷41 3
=7
×4÷4,1 3
=7
;1 3
⑥
,9
+81 9
-71 8 1 7 9
-51 9
+61 7 1 8
=
,(9+8-7)+(
+1 9
-1 8
)1 7 (9-5+6)+(
+1 9
-1 8
)1 7
=
,10+(
+1 9
-1 8
)1 7 10+(
+1 9
-1 8
)1 7
=1;
⑦(
×4.27+8.54×14 35
)÷4.27×25%,21 30
=(0.4×4.27+8.54×0.7)÷4.27×0.25,
=(1.708+5.978)×0.25÷4.27,
=7.686×0.25÷4.27,
=1.9215÷4.27,
=0.45;
⑧1
+31 6
+51 12
+71 20
+91 30
,1 42
=(1+3+5+7+9)+(
+1 6
+1 12
+1 20
+1 30
),1 42
=25+(
-1 2
+1 3
-1 3
+1 4
-1 4
+1 5
-1 5
+1 6
-1 6
),1 7
=25+(
-1 2
),1 7
=25+
,5 14
=25
.5 14