- Probability, Counting and Combinatorics
- Proportional Reasoning
- Sequences, Series and Patterns
According to “A History of Valentine’s Day Cards in America” by T.M. Wilson, in 1847 Esther Howland was the first to mass-produce Valentine’s Day cards. She made them out of lace, paint and expensive...
- Percents and Fractions
- Probability, Counting and Combinatorics
- Solid Geometry
The following information and problems were submitted by a MATHCOUNTS volunteer, Emily Koithan. Thank you, Emily! Neuroscientists use a special type of brain scanning called functional magnetic...
- Probability, Counting and Combinatorics
- Problem Solving (Misc.)
The 3rd Thursday in April (April 18, 2024) is National High Five Day! For National High Five Day, Ronnie’s class decides that everyone in the class should exchange one high five with each other person...
- Probability, Counting and Combinatorics
- Problem Solving (Misc.)
According to the North American Numbering Plan Administration (NANPA) standards, U.S. phone numbers contain a 3-digit area code, followed by a 3-digit exchange code and end in a 4-digit subscriber...