Number and Alphabet Series
intermediate24 min read
The patterns behind number series and alphabet series, the fixed routine for finding the next term, and the 'wrong term' variant where one entry breaks an otherwise clean rule.
What you will be able to do
- Test a number series for a difference, ratio, or square-and-cube pattern.
- Handle two-tier series where the differences themselves form a pattern.
- Find the single wrong term by assuming the rule from the majority of terms.
- Work an alphabet or alphanumeric series using letter position numbers.
What is inside this lesson
- 1What a series question asks
- 2The common number patterns
- 3The wrong-term variant
- 4Alphabet and alphanumeric series
- 5Worked examples
- 6Common mistakes
- 7Quick revision
- 8Practice
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What a series question asks
A series gives you an ordered list of numbers or letters built on one hidden rule, and asks for the next term, a missing middle term, or the one term that does not fit.
Three things to settle fast:
- Is it a number series, an alphabet series, or an alphanumeric stream mixing letters, digits and symbols?
- Is the trend rising fast (think multiplication or powers), rising slowly (think addition), or going up and down (think two interleaved series)?
- Are you asked for the next term or for the wrong term? The wrong-term variant is solved differently.
The lesson itself is for members
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