Missing Number
🔒 Log in to trackFigure-based puzzles — paired grids, single grids, circles — where one cell is hidden behind a numerical rule. Every rule connects the cells of a row (or segment), and the same rule is demonstrated by at least two complete instances. The winning habit is two-line verification: fit the rule on one complete row, confirm on the other, then apply. Digit-sum and digit-reversal variants reward students who switch families quickly when plain arithmetic stalls.
One page per subtopic: detailed notes, every question type, formulas, tricks and practice sets.
Every formula on one printable page, grouped by subtopic.
4 exam-level questions worked step by step.
45 questions — untimed practice or a timed test with analysis.
Track record in the exam
Questions per shift in recent SSC CGL papers.
Test difficulty mix (45 questions)
Question patterns exams keep repeating
Taken from previous-year papers. If a pattern is marked "very common", expect to see it in your exam.
Find the rule in rows
very commonA 3×3 grid with one missing number, and each row follows the same hidden rule.
Try simple rules on the complete rows: add, multiply, multiply then ± a number.
Use only a rule that fits every complete row.
Rows: (6, 3, 15), (8, 4, 28), (9, 5, ?)
Adding does not work (6 + 3 = 9)
15 = 5 × 3 and 28 = 7 × 4, so third = (first − 1) × second
Row 3: (9 − 1) × 5 = 40
Two grids, one rule
commonTwo full grids and a third grid with a missing number.
Find the rule in the first grid.
Check it on the second grid, then use it on the third.
Grid 1: (2, 3, 7), (3, 4, 13). Grid 2: (4, 5, ?), (5, 6, 31). Find ?
Try first × second + 1: 2 × 3 + 1 = 7 ✓
3 × 4 + 1 = 13 ✓ and 5 × 6 + 1 = 31 ✓
4 × 5 + 1 = 21
Rule with squares
commonThe answers are close to square numbers (like 26, 48, 50, 63).
Square one of the numbers and see what is left over.
Try a² − b, a² + b, a² + 1.
Rows: (4, 6, 10), (5, 3, 22), (7, 2, ?)
Try first² − second: 16 − 6 = 10 ✓
25 − 3 = 22 ✓
49 − 2 = 47
Triangle or circle with a centre number
commonNumbers are at the corners of a triangle (or sectors of a circle) with a number in the centre.
Test the sum and the product of the outer numbers.
Check the rule on every complete figure.
Triangles (corners → centre): (2, 3, 4 → 24), (1, 5, 6 → 30), (3, 2, 5 → ?)
Try the product of the corners: 2 × 3 × 4 = 24 ✓
1 × 5 × 6 = 30 ✓
3 × 2 × 5 = 30
Reversed-digit rule
commonTwo-digit numbers in the row, and the answers look like scrambled sums.
Reverse the digits of each number (23 becomes 32).
Then add them and compare.
Rows: (23, 14, 73), (45, 12, 75), (62, 23, ?)
Reverse and add: 32 + 41 = 73 ✓
54 + 21 = 75 ✓
Row 3: 26 + 32 = 58
Digit-product rule
occasionalThe answers are small compared with the two-digit numbers in the row.
Multiply the digits of each number.
Then add the two products and compare.
Rows: (24, 35, 23), (43, 26, 24), (52, 33, ?)
Digit products: 2 × 4 = 8 and 3 × 5 = 15; 8 + 15 = 23 ✓
4 × 3 = 12 and 2 × 6 = 12; 12 + 12 = 24 ✓
Row 3: 5 × 2 + 3 × 3 = 10 + 9 = 19
Digit-sum rule
commonThe answers are tiny compared with the numbers in the row.
Add the digits of each number, then add the two sums.
If it does not match, look for a fixed number left over.
Rows: (29, 14, 18), (38, 25, 20), (56, 34, ?)
Row 1: digit sums 11 and 5 make 16; answer 18, so add 2
Row 2: 11 + 7 + 2 = 20 ✓
Row 3: digit sums 11 and 7, so 11 + 7 + 2 = 20