问题
解答题
计算下面各题(能简算的要简算) ①19.76-4
②8
③2.5×1.25×32. |
答案
①19.76-4
-33 7
,4 7
=19.76-(4
+33 7
),4 7
=19.76-8,
=11.76;
②8
-87 10
+211 20
,11 12
=8+
-(8+7 10
)+(2+11 20
),11 12
=8+
-8-7 10
+2+11 20
,11 12
=(8-8+2)+(
-7 10
+11 20
),11 12
=2+1
,1 15
=3
;1 15
③2.5×1.25×32,
=2.5×1.25×4×8,
=(2.5×4)×(1.25×8),
=10×10,
=100.