急,简便运算:6/1+15/8+28/3-35/2-44/7还有:(2+5+8+。+2000)-(1+4+7+。+1999) 一又四分之一减20分之九加30分之11减42分之13加56分之15快的提高悬赏
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/11 18:37:46
![急,简便运算:6/1+15/8+28/3-35/2-44/7还有:(2+5+8+。+2000)-(1+4+7+。+1999) 一又四分之一减20分之九加30分之11减42分之13加56分之15快的提高悬赏](/uploads/image/z/17119-55-9.jpg?t=%E6%80%A5%2C%E7%AE%80%E4%BE%BF%E8%BF%90%E7%AE%97%EF%BC%9A6%2F1%2B15%2F8%2B28%2F3-35%2F2-44%2F7%E8%BF%98%E6%9C%89%EF%BC%9A%EF%BC%882%2B5%2B8%2B%E3%80%82%2B2000%EF%BC%89-%EF%BC%881%2B4%2B7%2B%E3%80%82%2B1999%EF%BC%89+%E4%B8%80%E5%8F%88%E5%9B%9B%E5%88%86%E4%B9%8B%E4%B8%80%E5%87%8F20%E5%88%86%E4%B9%8B%E4%B9%9D%E5%8A%A030%E5%88%86%E4%B9%8B11%E5%87%8F42%E5%88%86%E4%B9%8B13%E5%8A%A056%E5%88%86%E4%B9%8B15%E5%BF%AB%E7%9A%84%E6%8F%90%E9%AB%98%E6%82%AC%E8%B5%8F)
急,简便运算:6/1+15/8+28/3-35/2-44/7还有:(2+5+8+。+2000)-(1+4+7+。+1999) 一又四分之一减20分之九加30分之11减42分之13加56分之15快的提高悬赏
急,简便运算:6/1+15/8+28/3-35/2-44/7
还有:(2+5+8+。+2000)-(1+4+7+。+1999)
一又四分之一减20分之九加30分之11减42分之13加56分之15
快的提高悬赏
急,简便运算:6/1+15/8+28/3-35/2-44/7还有:(2+5+8+。+2000)-(1+4+7+。+1999) 一又四分之一减20分之九加30分之11减42分之13加56分之15快的提高悬赏
1.分子分母反过来看,
6/1应该是1/6(六分之一吧)
以此类推.
6/1+15/8+28/3-35/2-44/7
1/6+8/15+3/28-2/35-7/44
=(1/2-1/3)+(1/3+1/5)+(1/4-1/7)-(1/5-1/7)-(1/4-1/11)
=1/2-1/3+1/3+1/5+1/4-1/7-1/5+1/7-1/4+1/11
=1/2+1/11
=11/22+2/22
=13/22
2.
(2+5+8+.+2000)-(1+4+7+.+1999)
=(2-1)+(5-4)+(8-7)+...+(2000-1999)
=1×[(2000-2)÷(5-2)+1]
=1×667
=667
3.
1又1/4-9/20+11/30-13/42+15/56
=1+1/4-(4/20+5/20)+(5/30+6/30)-(6/42+7/42)+(7/56+8/56)
=1+1/4-1/5+1/4+1/6+1/5-1/6-1/7+1/7+1/8
=1+5/8
=1又5/8