简算 19/20+29/30+41/42+55/56+71/72
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/02 22:39:48
![简算 19/20+29/30+41/42+55/56+71/72](/uploads/image/z/16601-41-1.jpg?t=%E7%AE%80%E7%AE%97+19%2F20%2B29%2F30%2B41%2F42%2B55%2F56%2B71%2F72)
简算 19/20+29/30+41/42+55/56+71/72
简算 19/20+29/30+41/42+55/56+71/72
简算 19/20+29/30+41/42+55/56+71/72
19/20+29/30+41/42+55/56+71/72
=1- 1/20 +1 - 1/30 +1 -1/42 +1 -1/56 +1- 1/72
=5- (1/20 + 1/30 + 1/42 + 1/56 + 1/72)
=5-(1/4 - 1/5 +1/5 - 1/6+ 1/6 - 1/7 +1/7 -1/8 +1/8 -1/9)
=5 - (1/4 - 1/9)
=5 - 5/36
=4又31/36