题目内容
用简便方法计算.
7.5+9.9
48×
+0.1×48
×
+
×
-
1.25×16×0.5.
7.5+9.9
48×
| 9 |
| 10 |
| 4 |
| 7 |
| 4 |
| 5 |
| 2 |
| 5 |
| 4 |
| 7 |
| 4 |
| 7 |
1.25×16×0.5.
(1)7.5+9.9
=7.5+(10-0.1)
=7.5+10-0.1
=17.4
(2)48×
+0.1×48
=48×(
+0.1)
=48×1
=48
(3)
×
+
×
-
=
×(
+
-1)
=
×
=
(4)1.25×16×0.5
=1.25×(8×2)×0.5
=(1.25×8)×(2×0.5)
=10×1
=10
=7.5+(10-0.1)
=7.5+10-0.1
=17.4
(2)48×
| 9 |
| 10 |
=48×(
| 9 |
| 10 |
=48×1
=48
(3)
| 4 |
| 7 |
| 4 |
| 5 |
| 2 |
| 5 |
| 4 |
| 7 |
| 4 |
| 7 |
=
| 4 |
| 7 |
| 4 |
| 5 |
| 2 |
| 5 |
=
| 4 |
| 7 |
| 1 |
| 5 |
=
| 4 |
| 35 |
(4)1.25×16×0.5
=1.25×(8×2)×0.5
=(1.25×8)×(2×0.5)
=10×1
=10
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