2025 AMC 8 第 4 题
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所有题目均经美国数学协会（MAA）官方合法授权使用。
4.
Lucius 正在每次减 倒着数。他的前三个数是 、、。他的第 个数是多少？
Lucius is counting backward by s. His first three numbers are and What is his th number?
答案：B
小提示：
第 个数比第 个数晚 步
The th number is steps after the st
大提示：
从第一项连续减去九次七
Subtract nine 7s from the first term
视频讲解：
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文字解答：
从他的第一个数 到第 个数之间有 个间隔，每个间隔的大小都是 。
因此总共减去 ，从 剩下 ，选 B。
There will be gaps between his first number and his th number. Each gap has size
So, he will subtract a total of from leaving an answer of which is choice B.
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