问题
解答题
| 简便计算． （1）13
（3）（
|
答案
（1）13
-5.8+35 7
+4.22 7
=（13
+35 7
）-5.8+4.22 7
=17-5.8+4.2
=15.4；
（2）7.7÷1
+0.75×41 3 3 10
=7.7÷
+0.75×44 3 3 10
=7.7×
+0.75×43 4 3 10
=7.7×0.75+0.75×43 10
=0.75×（7.7+4
）3 10
=0.75×（7
+47 10
）3 10
=0.75×12
=9；
（3）（
-0.25+5 6
）×2.41 3
=（
-5 6
+1 4
）×2.41 3
=
×2.4-5 6
×2.4+1 4
×2.41 3
=5×0.4-0.6+0.8
=2-0.6+0.8
=2.2；
（4）2
×4.625+61 2
×250%-2.53 8
=2.5×4.625+6.375×2.5-2.5
=2.5×（4.625+6.375-2.5）
=2.5×8.5
=21.25．