Alphabet & Number Sequences
<p>Sequence questions give you a pattern of letters or numbers (or both) and ask you to find the next item, a missing item, or the rule. These are very common in the 11+ verbal reasoning exam.</p>
<h2>Number Sequences</h2>
<p>Look at the differences between consecutive numbers to find the pattern.</p>
<p><strong>Worked Example:</strong> 2, 5, 8, 11, 14, ?</p>
<p>Differences: +3, +3, +3, +3. The rule is add 3 each time. Next: 14 + 3 = 17.</p>
<p><strong>Worked Example:</strong> 3, 6, 12, 24, 48, ?</p>
<p>Differences: ×2, ×2, ×2, ×2. Each number doubles. Next: 48 × 2 = 96.</p>
<p><strong>Worked Example:</strong> 1, 4, 9, 16, 25, ?</p>
<p>These are square numbers: 1², 2², 3², 4², 5². Next: 6² = 36.</p>
<h2>Alternating Sequences</h2>
<p>Sometimes two separate sequences are interleaved (woven together).</p>
<p><strong>Worked Example:</strong> 2, 10, 4, 8, 6, 6, 8, ?</p>
<p>Separate into odd positions and even positions:<br>
Odd positions: 2, 4, 6, 8 (going up by 2)<br>
Even positions: 10, 8, 6, ? (going down by 2)<br>
Answer: 4.</p>
<h2>Letter Sequences</h2>
<p>Treat each letter as a number (A=1, B=2, ... Z=26) and look for the pattern.</p>
<p><strong>Worked Example:</strong> A, D, G, J, ?</p>
<p>A(1), D(4), G(7), J(10). Each letter is +3 positions in the alphabet. Next: 10 + 3 = 13 = M.</p>
<p><strong>Worked Example:</strong> Z, X, V, T, ?</p>
<p>Z(26), X(24), V(22), T(20). Each letter goes back by 2. Next: 20 − 2 = 18 = R.</p>
<h2>Letter-Number Mixed Sequences</h2>
<p><strong>Worked Example:</strong> A1, C3, E5, G7, ?</p>
<p>Letters: A, C, E, G (+2 each time) → next is I.<br>
Numbers: 1, 3, 5, 7 (+2 each time) → next is 9.<br>
Answer: I9.</p>
<h2>Pair Sequences</h2>
<p><strong>Worked Example:</strong> AB, CD, EF, GH, ?</p>
<p>Each pair uses the next two letters of the alphabet. Answer: IJ.</p>
<p><strong>Worked Example:</strong> AZ, BY, CX, DW, ?</p>
<p>First letters: A, B, C, D, E (going forward). Second letters: Z, Y, X, W, V (going backward). Answer: EV.</p>
<h2>Finding Missing Terms</h2>
<p>If the missing term is in the middle, work forwards from the left AND backwards from the right to confirm.</p>
<p><strong>Worked Example:</strong> 5, 10, ?, 40, 80</p>
<p>Each number doubles: 5 × 2 = 10, 10 × 2 = 20, 20 × 2 = 40, 40 × 2 = 80. Missing term: 20.</p>
<h2>Strategy Summary</h2>
<ol>
<li>Write out the differences (or ratios) between consecutive terms</li>
<li>If the differences are not constant, check if they form their own pattern</li>
<li>If the sequence looks strange, try splitting it into two interleaved sequences</li>
<li>For letters, convert to numbers to make the pattern clearer</li>
<li>Always verify your rule works for ALL given terms, not just the first two</li>
</ol>
<h2>Practice Tips</h2>
<ul>
<li>Write out the alphabet with numbers from A=1 to Z=26 until you can recall them instantly</li>
<li>Practise splitting alternating sequences — cover every other term with your finger</li>
<li>Time yourself: in the exam, spend about 30 seconds per sequence question</li>
<li>If a pattern is not obvious after 20 seconds, try a different approach (multiply instead of add, or check for squares/cubes)</li>
</ul>