题目内容
脱式计算(第1和第2小题用简便方法计算)
(1)14.5×64+64×4.5
(2)2.5×32×12.5
(3)(
+
)÷
+
(4)168.1÷(4.3×2-0.4)
(1)14.5×64+64×4.5
(2)2.5×32×12.5
(3)(
| 4 |
| 5 |
| 1 |
| 4 |
| 7 |
| 3 |
| 7 |
| 10 |
(4)168.1÷(4.3×2-0.4)
(1)14.5×64+64×4.5,
=64×(14.5+4.5),
=64×19,
=64×(20-1),
=64×20-64×1,
=1280-64,
=1216;
(2)2.5×32×12.5,
=2.5×4×8×12.5,
=(2.5×4)×(8×12.5),
=10×100,
=1000;
(3)(
+
)÷
+
,
=
×
+
,
=
+
,
=
;
(4)168.1÷(4.3×2-0.4),
=168.1÷(8.6-0.4),
=168.1÷8.2,
=20.5.
=64×(14.5+4.5),
=64×19,
=64×(20-1),
=64×20-64×1,
=1280-64,
=1216;
(2)2.5×32×12.5,
=2.5×4×8×12.5,
=(2.5×4)×(8×12.5),
=10×100,
=1000;
(3)(
| 4 |
| 5 |
| 1 |
| 4 |
| 7 |
| 3 |
| 7 |
| 10 |
=
| 21 |
| 20 |
| 3 |
| 7 |
| 7 |
| 10 |
=
| 9 |
| 20 |
| 14 |
| 20 |
=
| 23 |
| 20 |
(4)168.1÷(4.3×2-0.4),
=168.1÷(8.6-0.4),
=168.1÷8.2,
=20.5.
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