问题
解答题
用简便方法计算下列各题: ①
|
答案
①
+11 12
+5 8
+3 8 1 12
=(
+5 8
)+(3 8
+11 12
),1 12
=1+1,
=2;
②5-
-3 7 4 7
=5-(
+3 7
),4 7
=5-1,
=4;
③
×20+2 5
×203 5
=(
+2 5
)×20,3 5
=1×20,
=20.
用简便方法计算下列各题: ①
|
①
+11 12
+5 8
+3 8 1 12
=(
+5 8
)+(3 8
+11 12
),1 12
=1+1,
=2;
②5-
-3 7 4 7
=5-(
+3 7
),4 7
=5-1,
=4;
③
×20+2 5
×203 5
=(
+2 5
)×20,3 5
=1×20,
=20.