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(2009•高县)用简便方法计算.772-317+128-283=12.9×3.6+12.9×6.4=9-713-513=

题目详情
(2009•高县)用简便方法计算.
772-317+128-283=
12.9×3.6+12.9×6.4=
9-
7
13
-
5
13
=
▼优质解答
答案和解析
(1)772-317+128-283
=(772+128)-(317+283),
=900-600,
=300;

(2)12.9×3.6+12.9×6.4
=(3.6+6.4)×12.9,
=10×12.9,
=129;

(3)9-
7
13
-
5
13

=9-(
7
13
+
5
13
),
=9-
12
13

=8
1
13