TRAININg: Second Quarter Puzzles

Chess

Level 1: Unrated-700 USCF

GM Mariya Muzychuk vs. WIM Iris Mou (FIDE Women’s World Blitz Championship 2024), 0-1

Black to Play and Win!

Level 2: 600-1200 USCF

IM Alina Kashlinskaya vs. WIM Iris Mou (FIDE Women’s World Blitz Championship 2024), 0-1

Black to Play and Win!

Level 3: 1200 USCF+

WIM Iris Mou vs. Alisher Podavanov (Spring 2024 IM C Scheveningen), 1-0


White to Play and Win!

Math

Level 1:

How many triangles are in the following image?

(Hint: It’s a bit of a trick question… count carefully!)

Level 2:

Carl Friedrich Gauss, a German mathematician, proved that the sum of 1+2+3+…+n where n is any positive integer can be found with the following formula: [n*(n+1)]/2.

What is the sum of numbers 1+2+3+…+200?

(Hint: Use Gauss’s formula! For example: the sum of 1+2+3+…+10 = [10*(10+1)]/2 = 55).

Level 3:

Audrey flips a coin five times (the result is either heads or tails with equal probability of either). What is the probability she will flip at least four heads?

(Hint 1: Search up a probability tree.)

(Hint 2: How many heads does she need to flip out of five to get at least four? Search up casework.)