题目内容
①
|
②
|
③
| ||||||||||||||||||
④(3-1.4)÷
|
⑤解方程:
|
⑥解方程:x-15%x=37.4. |
分析:(1)先算乘法,再算加法,
(2)从左向右进行计算即可,
(3)运用乘法的分配律进行简算,
(4)先算小括号里的减法,再算括号外的除法,
(5)根据等式的基本性质,方程的两边同时乘以2,再同时除以
求解即可,
(6)先化简方程,再根据等式的基本性质,方程的两边同时除以85%求解即可.
(2)从左向右进行计算即可,
(3)运用乘法的分配律进行简算,
(4)先算小括号里的减法,再算括号外的除法,
(5)根据等式的基本性质,方程的两边同时乘以2,再同时除以
| 4 |
| 5 |
(6)先化简方程,再根据等式的基本性质,方程的两边同时除以85%求解即可.
解答:解:(1)
+
×
,
=
+
,
=
;
(2)
×3÷
,
=
÷
,
=12;
(3)
×
-
×
,
=(
-
)×
,
=
×
,
=
;
(4)(3-1.4)÷
,
=1.6÷
,
=3;
(5)
x÷2=
,
x÷2×2=
×2,
x=
,
x÷
=
÷
,
x=
;
(6)x-15%x=37.4,
85%x=37.4,
85%x÷85%=37.4÷85%,
x=44.
| 1 |
| 6 |
| 5 |
| 6 |
| 5 |
| 6 |
=
| 1 |
| 6 |
| 25 |
| 36 |
=
| 31 |
| 36 |
(2)
| 16 |
| 5 |
| 4 |
| 5 |
=
| 48 |
| 5 |
| 4 |
| 5 |
=12;
(3)
| 7 |
| 8 |
| 12 |
| 11 |
| 3 |
| 8 |
| 12 |
| 11 |
=(
| 7 |
| 8 |
| 3 |
| 8 |
| 12 |
| 11 |
=
| 1 |
| 2 |
| 12 |
| 11 |
=
| 6 |
| 11 |
(4)(3-1.4)÷
| 8 |
| 15 |
=1.6÷
| 8 |
| 15 |
=3;
(5)
| 4 |
| 5 |
| 7 |
| 16 |
| 4 |
| 5 |
| 7 |
| 16 |
| 4 |
| 5 |
| 7 |
| 8 |
| 4 |
| 5 |
| 4 |
| 5 |
| 7 |
| 8 |
| 4 |
| 5 |
x=
| 35 |
| 32 |
(6)x-15%x=37.4,
85%x=37.4,
85%x÷85%=37.4÷85%,
x=44.
点评:此题考查了分数、小数四则混合运算的顺序及利用等式的基本性质来求方程的解,解方程时注意等号对齐.
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