问题
解答题
脱式计算,能简算的要简算. ①0.25×
②
③(84%÷3+8.72)×(1-
④12×(
|
答案
①0.25×
+75 31
×25%49 31
=
×1 4
+75 31
×49 31 1 4
=
×(1 4
+75 31
)49 31
=
×41 4
=1;
②
÷(1-7 10
×3 4
)2 5
=
÷(1-7 10
)3 10
=
÷7 10 7 10
=1;
③(84%÷3+8.72)×(1-
)1 9
=(0.84÷3+8.72)×8 9
=(0.28+8.72)×8 9
=9×8 9
=9;
④12×(
-1 2
)3 4
=12×
-12×1 2 3 4
=6-9
=-3.