用简便方法计算. (1)3.14× 3 5 +3.14× 2 5 (2) 1 4 5 ×2

2024-11-25 20:44:30
推荐回答(1个)
回答1:

(1)3.14×
3
5
+3.14×
2
5

=3.14×(
3
5
+
2
5
),
=3.14×1,
=3.14;

(2) 1
4
5
×25%+
1
4
×2.2,
=1.8×
1
4
+
1
4
×2.2,
=
1
4
×(1.8+2.2),
=
1
4
×4,
=1;

(3)87.5×19-87.5×8-87.5,
=87.5×19-87.5×8-87.5×1,
=87.5×(19-8-1),
=87.5×10,
=875;

(4)0.77×(
6
7
+
2
11
),
=0.77×
6
7
+0.77×
2
11

=0.66+0.14,
=0.8.