Today's PUZZLE CLASSIC OF THE DAY

How many triangles can you count in this diamond?

A bag contains either a red ball or a blue ball. A red ball is then dropped into the bag, so now it has 2 balls. A drawing is held, and a red ball is drawn out of the bag. What’s the probability of the remaining ball also being red?

How many regular hexagons are engraved on this stone? The biggest one is already counted toward the overall pool.

Place the numbers 1-12, sans 9, into the "atoms" of this crystal lattice so that each row totals 20. Two additional numbers are already placed in it - 5 and 15.

How many different pentagons are in this shape?

Cut this figure into four congruent parts, each of which would contain two screws and one opening.

How many triangles (one or more segments) can you count in this image?

There are four brothers in a family. The sum of the ages of each combination of three brothers: 30, 32, 32, and 35. How old is the oldest brother?

What is the largest number that can be made by multiplying two three-digit numbers together using each of the digits from 1 to 6 exactly once? Example: 134 × 256 = 34,304, though this is not the largest number that can be made. What is?

Turn off the numbers until you end up with only one number.

Sierra is standing behind Giselle. And Giselle is standing behind Sierra. This doesn't seem possible but it is. How?

Arrange four 9's and a 1, and ONLY ONE basic arithmetic operator (-, +, /, or x) into a mathematical expression with a result equal to 100. NOTE: All 5 numbers must be used (e.g. 99 + 1 is not valid).