分析:通过仔细观察,把每个分数可以分成两部分,原式变为(
+
+
+
+
+
+
)+(2+4+8+16+32+64),然后把第一个括号内的数调整一下运算顺序,即(
+
+
+
+
+
+
)+126,发现后一个分数是前一个分数的
,于是把每个分数拆成两个分数相减的形式,然后通过加减相互抵消,求出结果.
1 |
128 |
1 |
64 |
1 |
32 |
1 |
16 |
1 |
8 |
1 |
4 |
1 |
2 |
1 |
2 |
1 |
4 |
1 |
8 |
1 |
16 |
1 |
32 |
1 |
64 |
1 |
128 |
1 |
2 |
解答:解:
+2
+4
+8
+16
+32
+64
,
=(
+
+
+
+
+
+
)+(2+4+8+16+32+64),
=(
+
+
+
+
+
+
)+126,
=(1-
+
-
+
-
+
-
+
-
+
-
+
-
)+126,
=(1-
)+126,
=
+126,
=126
.
1 |
128 |
1 |
64 |
1 |
32 |
1 |
16 |
1 |
8 |
1 |
4 |
1 |
2 |
=(
1 |
128 |
1 |
64 |
1 |
32 |
1 |
16 |
1 |
8 |
1 |
4 |
1 |
2 |
=(
1 |
2 |
1 |
4 |
1 |
8 |
1 |
16 |
1 |
32 |
1 |
64 |
1 |
128 |
=(1-
1 |
2 |
1 |
2 |
1 |
4 |
1 |
4 |
1 |
8 |
1 |
8 |
1 |
16 |
1 |
16 |
1 |
32 |
1 |
32 |
1 |
64 |
1 |
64 |
1 |
128 |
=(1-
1 |
128 |
=
127 |
128 |
=126
127 |
128 |
点评:此题运用了分数的拆分,使复杂的问题简单化.