用简便方法计算:4+14+24+34+44+54+64+74+84+94+104+114+124+134=?
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/28 16:46:39
![用简便方法计算:4+14+24+34+44+54+64+74+84+94+104+114+124+134=?](/uploads/image/z/32831-71-1.jpg?t=%E7%94%A8%E7%AE%80%E4%BE%BF%E6%96%B9%E6%B3%95%E8%AE%A1%E7%AE%97%EF%BC%9A4%2B14%2B24%2B34%2B44%2B54%2B64%2B74%2B84%2B94%2B104%2B114%2B124%2B134%3D%3F)
用简便方法计算:4+14+24+34+44+54+64+74+84+94+104+114+124+134=?
用简便方法计算:4+14+24+34+44+54+64+74+84+94+104+114+124+134=?
用简便方法计算:4+14+24+34+44+54+64+74+84+94+104+114+124+134=?
等差数列,每一项都是相差10
S=(4+134)*14/2=138*7=966
就跟从1一直加到100结果等于5050是一样的道理