This Week's Work : Week 51 for Inquisitive Young Mathletes

For this week's work :

Try 2013 Mathworks Math Contest problems from Texas State University

Answer key and statistics can be viewed here. 

I'll send you detailed solutions once we finish all the problems.

Practice more "at least" problems :

2014 AMC-10 B problem 16 

Solution

From Mathcounts Mini : Video tutorials on counting and probability for Mathcounts state/national prep concepts are in order the of difficulty.

Counting the Number of Subsets of a Set

Constructive Counting

More Constructive Counting 

Probability and Counting

This Week's Work : Week 50 - for Inquisitive Young Mathletes

Counting Restrictions from Glyia

Very nice introductory level counting questions with restrictions.

from Mathcounts Mini : Counting the Number of Subsets of a Set

 from AoPS :

Counting with Restrictions Part 3  : This one is tricky. Make sure you understand the concepts well.

Try this question from 2011 AMC-8 # 23 :

How many 4-digit positive integers have four different digits, where the leading digit is not zero, the integer is a multiple of 5, and 5 is the largest digit?

Solutions from AoPS

Counting with Combinations Part 3

At our group lessons, we'll continue working on harder Mathcounts concepts, not just the accuracy, but speed.

Take care and happy problem solving !!