First of all, congratulations to the following students in our class who have won in the recent school wide Math contest:<\/p>\n
Karen Li is the sole 1st place winner in the \u00a06th grade category with $20 prize.<\/p>\n
Eugene Jiang, Robert Sheng, Alexander Deng, Jiming Xu are among other prize winners in the 6th grade category and will each get $10 prize.<\/p>\n
Congratulations again!<\/p>\n
Since we have finished covering the regular content in the textbook, I am adding a little more today. For the last two lessons, we will have review and final exam.<\/p>\n
We study combinations and permutations, with the introduction of factorial. A combination is a group of outcomes where the order does not matter, while permutation is a group of outcomes where the order does matter. Factorial is a way of computation. The factorial of a number is the product of the number and all the natural numbers less than the number.<\/p>\n
n! = n x (n-1) x (n-3) x … x 3 x 2 x 1<\/p>\n
The number of permutations of choosing r things out of n things at a time is denoted as nPr and<\/p>\n
nPr = n! \/ (n-r)!<\/p>\n
The number of combinations of choosing r things out of n things at a time is denoted as nCr and<\/p>\n
nCr = n! \/ [r! x (n-r)!]<\/p>\n
Today’s material can be found here<\/a> for Section 10.8.<\/p>\n