| 计算。 | |
24.7-11 -9![]() |
1-0.125÷![]() |
84×0.25+ ×16 |
(2.5+3.6)×2 +3.9×2![]() |
0.875× +0.125÷2 |
-30%×0.2÷50% |
解:①24.7-11
-9
,
=24.7-(11
+9
),
=24.7-20
,
=4
;
②1-0.125÷
,
=1-0.125÷0.125,
=1-1,
=0;
③84×0.25+
×16,
=84×0.25+0.25×16,
=0.25×(84+16),
=0.25×100,
=25;
④(2.5+3.6)×2
+3.9×2
,
=2
×(2.5+3.6+3.9),
=
×10,
=22.5;
⑤0.875×
+0.125÷2,
=0.875×
+0.125×
,
=
×(0.875+0.125),
=
×1,
=
⑥
-30%×0.2÷50%,
=0.5-0.3×0.2÷0.5,
=0.5-0.12,
=0.38
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=( )(填小数)。[ ]
a.缩小为原来的[ ]
[ ]
a.4.5÷l.5
,那么积[ ]
a.扩大为原来的5倍
,另一个因数不变,积[ ]
a.扩大为原来的100倍