1. Students in Mac's room had an estimation contest. The student whose estimate is the closest to the numbers in the jar wins the contest. Caroline, who estimated 135 marbles, won the contest. Alex, who estimated 150 marbles, got second place. Lucy, who estimated 152 marbles, got third place. And Melanie, who estimated 131 marbles, got fourth place. What is the exact number of marbles in the jar?

2. Can you find 3 numbers (a,b,c) such that a! * b! = c! and a<b<c <25.

3. Algebra exercises often ask students to "Find n." But you will not find 'n' in this brainteaser.

Create an equation of the form c = ab such that:

1. when written out in English, none of the numbers a, b, or c contain the letter 'n'.

2. a, b, and c are all integers.

3. c has the largest value possible

4. It's not too hard to form the number 9 using three 3's and any of the four standard mathematical operations-addition, subtraction, multiplication, and division. But can you come up with four different solutions, each of which uses only one of the four operations? (Other standard mathematical symbols can be used as needed.)