问题
解答题
用你喜欢的方法算：
|
答案
①
÷7+5 12
×7 12 1 7
=
×5 12
+1 7
×7 12 1 7
=（
+5 12
）×7 12 1 7
=1×1 7
=
；1 7
②
-（7 8
-5 9
）1 8
=
-7 8
+5 9 1 8
=（
+7 8
）-1 8 5 9
=1-5 9
=
；4 9
③
+1 6
×3 4
÷22 3
=
+1 6
×3 4
×2 3 1 2
=
+1 6 1 4
=
；5 12
④
×（12 5
+5 6
）+3 4 4 5
=
×12 5
+5 6
×12 5
+3 4 4 5
=2+
+9 5 4 5
=2+（
+9 5
）4 5
=2+13 5
=4
．3 5