1、 0.525÷13.125÷4×85.2 2、 7142.85÷3.7÷2.7×1.7×0.73、 1+2-3+4+5-6+7+8+9+10+11-12+……+97+98-99最好写出怎么简便和综合算式!是加九 在世界外国语中学里的题目是+9 如果不能做就说 我加了五分

0.525÷13.125÷4×85.2
=0.525÷(13.125×4)×85.2
=0.525÷52.5×85.2
=0.01×85.2
=0.852
7142.85÷3.7÷2.7×1.7×0.7
=7142.85÷37÷27×17×7
=7142.85×7÷999×17
=49999.95÷999×17
=50.05×17
=850.85

0.525÷13.125÷4×85.2=0.525÷(13.125×4)×85.2=0.525÷52.5×85.2=0.01×85.2=0.852
7142.85÷3.7÷2.7×1.7×0.7=1930.5÷2.7×1.7×0.7=715×1.7×0.7=1215.5×0.7=1216.2

0.525÷13.125÷4×85.2
=0.525÷(13.125×4)×85.2
=0.525÷52.5×85.2
=0.01×85.2
=0.852
7142.85÷3.7÷2.7×1.7×0.7
=1930.5÷2.7×1.7×0.7
=715×1.7×0.7
=1215.5×0.7
=1216.2
是“1+2-3+4+5-6+7+8-9+10+11-12+……+97+98-99”吧？
三十三组，每组所减的数比前一个数大1，
=（1+4+7+10+13+....+97）-33
=3201

0.525/13.125/4*85.2
=0.525/(5*5*0.525)/4*85.2
=(1/25)/4*85.2
=0.04/(0.04*100)*85.2
=(1/100)*85.2
=0.01*85.2
=0.852
7142.85÷3.7÷2.7×1.7×0.7
=7142.85÷37÷27×17×7
=7142.85×7÷999×17
=49999.95÷999×17
=50.05×17
=850.85
第三题你确定是+9不是-9？

1. 0.525÷13.125÷4×85.2
=0.525÷(13.125×4)×85.2
=0.525÷52.5×85.2
=0.01×85.2
=0.852
2. 7142.85÷3.7÷2.7×1.7×0.7
=7142.85÷37÷27×17×7
=7142.85×7÷999×17
=49999.95÷999×17
=50.05×17
=850.85
3. 1+2-3+4+5-6+7+8-9+…+97+98-99．
=（1+2+3+4+…+97+98+99）-2×（3+6+9+…+99）
=（1+99）×99÷2-2×（3+99）×33÷2
=4950-3366
=1584。

1、0.525÷13.125÷4×85.2
=0.525÷(13.125×4)×85.2
=0.525÷52.5×85.2
=0.01×85.2
=0.852
2、7142.85÷3.7÷2.7×1.7×0.7
=7142.85÷37÷27×17×7
=7142.85×7÷999×17
=49999.95÷999×17
=50.05×17
=850.85
3、你的题目……+9？
如果是-9的话 同等于3+6+9+……+96=1584

1+2-3+4+5-6+7+8-9+…+97+98-99．
分析 把原题作适当的变形,然后再利用等差数列的求和公式计算．
解1+2-3+4+5-6+7+8-9+…+97+98-99
=（1+2+3+4+…+97+98+99）-2×（3+6+9+…+99）
=（1+99）×99÷2-2×（3+99）×33÷2
=4950-3366=1584.
一定要采用哦!我算了很长时间呢!

1.0.525/13.125/4*85.2
=0.525/(5*5*0.525)/4*85.2
=(1/25)/4*85.2
=0.04/(0.04*100)*85.2
=(1/100)*85.2
=0.01*85.2
=0.852
2.7142.85÷3.7÷2.7×1.7×0.7
=7142.85÷37÷27×17×7
=7142.85×7÷999×17
=49999.95÷999×17
=50.05×17
=850.85
3.(1+98)+(2+97)+...-99=49*99-99=4752