数学数列问题咨询：求数列第4项及七年级数列空缺项选择

Hey there! Let's break down this 7th-grade math sequence problem together.

The Problem #

请为数列9, 4, 10, 11, ...... , 26的空缺处选择正确数字，选项为(a) 16 (b) 18 (c) 24 (d) 32。

Step-by-Step Analysis #

First, let's test common sequence patterns to uncover the rule here:

• Let's check how each term connects to the two preceding terms:
  • 9 + 4 - 3 = 10 (this matches the third term perfectly)
  • 4 + 10 - 3 = 11 (this lines up with the fourth term)
  • Apply the same rule to find the missing term: 10 + 11 - 3 = 18
  • Double-check with the final given term: 11 + 18 - 3 = 26 (this exactly matches the last term in the sequence!)

Conclusion #

The missing number is 18, which corresponds to option (b).

内容的提问来源于stack exchange，提问作者Sahan Aloka Mendis