问题
解答题
脱式计算.(能简算的要简算)
|
答案
(1)21×
×5 14 7 5
=21×(
×5 14
)7 5
=21×1 2
=21 2
(2)30×(
+2 5
-1 6
)4 15
=30×
+30×2 5
-30×1 6 4 15
=12+5-8
=9
(3)24×
+56÷3 8 8 3
=24×
+56×3 8 3 8
=(24+56)×3 8
=80×3 8
=30
(4)0.25×32×12.5
=0.25×4×8×12.5
=(0.25×4)×(8×12.5)
=1×100
=100
(5)
÷3 25
+1 10 1 5
=
×10+3 25 1 5
=
+6 5 1 5
=7 5
(6)
×[8 9
-(3 4
-7 16
)]1 4
=
×[8 9
+3 4
-1 4
]7 16
=
×[1-8 9
]7 16
=
×8 9 9 16
=1 2