Circle puzzles often require thinking backwards. Can you follow the arrows both ways to find the number behind the question mark?
3,835 people working on this
By balancing a chemical equation, we can compare masses of substances taking part in the reaction. What can you say about the mass of sulfuric acid?
5,583 people working on this
Partners want to sit next to each other while dining at a round table. In how many ways can they do that?
7,870 people working on this
In some games, it’s possible to play perfectly. Do we know the winner of this game before it even starts?
8,328 people working on this
Information about average prices of various school supplies allows us to put their prices in order. Which one is the cheapest?
7,774 people working on this
The adoption files for five dogs of different breeds and weights got mixed up. Using these clues, can you figure out who’s who?
8,260 people working on this
We can use the Pythagorean theorem to find sides of a right triangle. Can you find a right triangle in this trapezoid?
9,738 people working on this