# Alfredo Perez Resident Mathematician Texas A&M University GK-12 Program.

## Presentation on theme: "Alfredo Perez Resident Mathematician Texas A&M University GK-12 Program."— Presentation transcript:

http://brainimprovement.info/images/brain-power.jpg Alfredo Perez Resident Mathematician Texas A&M University GK-12 Program

Factorization is a very important concept in mathematics Before learning factorization, you must become familiar with the rules of divisibility By knowing divisibility rules, you can find the factors of any number very easily!

A NUMBER IS DIVISIBLE BY 2 IF the last digit is even (0,2,4,6, or 8) 3 IF the sum of all the digits gives a number that can be divided by 3 4 IF the last two digits together can be divided by 4 5 IF the last digit is a 5 or a 0 6 IF the number is divisible by both 2 and 3 8 IF the last three digits together can be divided by 8 9 IF the sum of all the digits gives a number that can be divided by 9 10 IF the last digit is a 0 The most important to know… RECALL: All numbers are divisible by 1

12,632Divisible by 2 because the number is even 14,361Divisible by 3 because the sum of the digits gives a number that can be divided by 3 1 + 4 + 3 + 6 + 1 = 15 15 divided by 3 = 5 No remainder 99,764Divisible by 4 because the last two digits together can be divided by 4 64 divided by 4 = 16 No remainder 37,995Divisible by 5 because the number ends in 5 29,742Divisible by 6 because the number is divisible by both 2 & 3 2 + 9 + 7 + 4 + 2 = 24 24 divided by 3 = 8 No remainder

2 + 9 + 7 + 4 + 2 = 24 2 + 4 = 6 6 divided by 3 = 2 A number divisible by 9 is automatically divisible by 3 also, but the opposite is not always true A number divisible by 8 is automatically divisible by 4 and by 2, but the opposite is not always true A number divisible by 4 is automatically divisible by 2, but the opposite is not always true A number divisible by 10 is automatically divisible by 5, but the opposite is not always true If the sum of the digits gives a large number when checking if a number is divisible by 3, continue adding the digits: 5 + 7 + 8 + 1 + 9 + 5 + 6 + 4 = 45 4 + 5 = 9 9 divided by 3 = 3 57,819,564 29,742 Ex:

A Memory Game You must know ALL Divisibility Rules

There are two decks of cards: One deck includes Divisibility Rule definitions The other includes Phrases that match the definitions Play in groups of two Place all cards over your desk, facing down Oldest person goes first: Flip one card from each deck without moving them from their position If the Phrase matches the Divisibility Rule definition: Keep the cards and continue with your turn If the cards don’t match: Put them back face down and let the other player continue Play until all cards have been taken Player with the most card pairs WINS!