Reasoning topic
An alphanumeric series mixes letters, numbers and sometimes symbols in each term. Each part of a term can follow its own rule, so take the terms apart and read one part at a time.
A typical question asks for the term that fits the blank. Other questions ask for the one term that breaks the pattern.
One term is missing from the series below. What is it? *O4, *P5, ?, *R7, *S8, *T9
*Q6
The * stays. The letters run O, P, Q, R and the numbers 4, 5, 6, 7, so the blank is *Q6.
Split each term into its parts: symbols, letters and numbers. Write each part as a series of its own.
Turn letters into positions, A = 1 to Z = 26. Then read each part as a number series: the gaps, a run you know such as squares or cubes, or a cycle that repeats. Past Z, take away 26.
If the terms jump about, read the odd places and the even places as two series. Then count which place the blank is in, and continue that series.
One term is missing from the series below. What is it? C3, X9, D4, ?, E5, V7
Answer: W8
1. Can you figure out what goes in the blank? T1, Q8, N27, ?, H125
Read the letters and the numbers apart. Do the numbers look like a run you know?
K64
Letters: T, Q, N, ?, H, at 20, 17, 14, ?, 8, falling by 3. The blank is 11, which is K.
Numbers: 1, 8, 27, ?, 125 are the cubes 1³, 2³, 3³, 4³ and 5³, so the blank is 4³ = 64. The term is K64.
2. Find the missing term in the series: %H1, @I3, #J6, %K10, ?, #M21
Each term has three parts: a symbol, a letter and a number. Read each part on its own.
@L15
Symbols: %, @, #, %, ?, #. They repeat in threes, so the 5th is @. Letters: H, I, J, K, ?, M, one step at a time, so the blank is L.
Numbers: 1, 3, 6, 10, ?, 21. The gaps are 2, 3 and 4, so the next is 5: 10 + 5 = 15. Check: 15 + 6 = 21. The term is @L15.
3. There is an incorrect term in the series below. Can you spot it? AN36, BO25, CP16, DS9, ER4
Read the first letters, the second letters and the numbers as three series.
DS9
First letters: A, B, C, D, E, one step at a time. Numbers: 36, 25, 16, 9, 4, the squares from 6² down to 2².
Second letters: N, O, P, S, R. N, O and P go up by one, so the fourth should be Q, and Q to R carries on to the last term. DS9 is the incorrect one; it should be DQ9.
Practise Alpha-numeric Series in the app. The questions follow your level, and what you practise comes back just before you'd forget it.
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