In a 5x5 grid of numbers from 1 to 25, what is the sum of all numbers in the first two rows?
Category: Math · Difficulty: hard
Hint: Calculate the sum of an arithmetic series.
Answer
165
Explanation
The first two rows contain numbers 1 to 10; summing gives 1+2+...+10 = 55; repeated for rows leads to 165.
This is a hard math riddle — a tricky one that takes a little thought. The answer is 165.
More Math riddles
- I am essential for building, yet I am invisible. You depend on me but may not see me. What am I?
- Multiply one by any number, what is the usual result?
- I can flip your expectations upside down, yet my essence remains unchanged. What am I?
- I start at a point, then I reduce, halving myself over and over, what's the truth? What am I?
- I can be shared out evenly or grouped in a set. My nature allows for flexibility, yet I am not a net. What…
- I can go on forever, my terms may be small. Add me together, and I may seem like nothing at all. What am I?
- I can be greater than ten but less than a score. My digits may change, but my value stays core. What am I?
- I am a set of three numbers that can form a right triangle. What am I?