Intelligent Math Puzzle – Challenge 82
Intelligent Math Puzzle – Challenge 82 shows three crosses of five numbers each. Two are complete and the third has a gap in the middle. The rule connecting the four outer numbers to the centre is the same in all three.
Challenge:
Three crosses are shown. In the first, the top, left, centre, right and bottom numbers are 3, 8, 22, 4 and 6. In the second they are 1, 7, 48, 3 and 9. In the third they are 11, 15, ?, 2 and 5. What number should replace the question mark?
The Answer
The correct answer is 78.
In each cross, add the left number to the top number, then multiply by the right number subtracted from the bottom number:
centre = (left + top) × (bottom − right)
First cross: (8 + 3) × (6 − 4) = 11 × 2 = 22. ✓
Second cross: (7 + 1) × (9 − 3) = 8 × 6 = 48. ✓
Applying the same rule to the third cross: (15 + 11) × (5 − 2) = 26 × 3 = 78.

Original price was: $27.99.$17.99Current price is: $17.99.
Related to This Article
More math articles
- 9 Best Math Websites for Teachers and Students
- BMR Calculator
- ALEKS Math Formulas: Study Reference and Examples
- The Best Grade 6 ELA Practice Tests for Pennsylvania Students
- Schools
- Alaska Algebra 1 Free Worksheets: Standards-Aligned Algebra 1 Practice PDFs, No Signup
- 3rd Grade K-PREP Math Worksheets: FREE & Printable
- NCLEX-PN Recognize vs. Analyze Cues: A Two-Pass Practice Worksheet (2027 Prep)
- Elapsed Time for 5th Grade: Find Duration and End Times
- Ratio, Proportion and Percentages Puzzle – Challenge 25













What people say about "Intelligent Math Puzzle – Challenge 82 - Effortless Math"?
No one replied yet.