题目内容
简便运算:
(1)2.9+29.9+299.9+2999.9
(2)(
+
)÷
×5.
(1)2.9+29.9+299.9+2999.9
(2)(
| 5 |
| 9 |
| 7 |
| 18 |
| 1 |
| 18 |
(1)2.9+29.9+299.9+2999.9,
=3-0.1+30-0.1+300-0.1+3000-0.1,
=3+30+300+3000-(0.1+0.1+0.1+0.1),
=3333-0.4,
=3332.6;
(2)(
+
)÷
×5,
=(
+
)×18×5,
=
×18×5+
×18×5,
=50-35,
=15.
=3-0.1+30-0.1+300-0.1+3000-0.1,
=3+30+300+3000-(0.1+0.1+0.1+0.1),
=3333-0.4,
=3332.6;
(2)(
| 5 |
| 9 |
| 7 |
| 18 |
| 1 |
| 18 |
=(
| 5 |
| 9 |
| 7 |
| 18 |
=
| 5 |
| 9 |
| 7 |
| 18 |
=50-35,
=15.
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